USP10 regulates p53 localization and stability by deubiquitinating p53.

Stability and localization of p53 is essential for its tumor suppressor function. Ubiquitination by the E3 ubiquitin ligase Mdm2 is the major regulatory mechanism of p53, which induces p53 nuclear export and degradation. However, it is unclear whether ubiquitinated cytoplasmic p53 can be recycled. Here, we report that USP10, a cytoplasmic ubiquitin-specific protease, deubiquitinates p53, reversing Mdm2-induced p53 nuclear export and degradation. After DNA damage, USP10 is stabilized, and a fraction of USP10 translocates to the nucleus to activate p53. The translocation and stabilization of USP10 is regulated by ATM -mediated phosphorylation of USP10 at Thr42 and Ser337. Finally, USP10 suppresses tumor cell growth in cells with wild-type p53, with USP10 expression downregulated in a high percentage of clear cell carcinomas, known to have few p53 mutations. These findings reveal USP10 to be a novel regulator of p53, providing an alternative mechanism of p53 inhibition in cancers with wild-type p53.

DNA Methylation and p53 Immunohistochemistry as Prognostic Biomarkers for Vulvar Lichen Sclerosus.

Vulvar lichen sclerosus (LS) is an inflammatory dermatosis that can progress to human papillomavirus (HPV)-independent vulvar intraepithelial neoplasia (HPVi VIN) and vulvar squamous cell carcinoma (VSCC). Although LS has a much lower cancer risk compared with HPVi VIN (5% vs 50%, respectively), its incidence is significantly higher. Therefore, there is a clinical need to identify LS patients with an increased cancer risk. Our objective was to study the value of DNA methylation and p53 immunohistochemistry (IHC) as prognostic biomarkers for progression to cancer in patients with LS. Vulvar tissues from 236 patients were selected, including 75 LS and 68 HPVi VIN, both with and without cancer development, 32 VSCC, and 61 healthy vulvar controls. Samples were subjected to p53 IHC and DNA methylation analysis of a 3-gene marker panel containing ZNF582, SST, and miR124-2. Methylation levels and p53 IHC status (mutant or wild-type) were assessed and compared among all disease categories. Odds ratios were determined to identify whether the biomarkers were associated with progression to cancer in patients with LS. The highest methylation levels were found in HPVi VIN and VSCC, followed by LS and healthy vulvar controls. The largest heterogeneity in methylation levels was observed in LS cases. In fact, the 3-marker panel tested positive in 70% of LS, which progressed to VSCC vs only 17% of LS in patients without cancer development (P = .002). Also, mutant p53 IHC was observed more frequently in LS with progression to VSCC compared with nonprogressive LS cases (42% vs 3%, respectively, P = .001). Multivariable analysis identified a mutant p53 status as the only independent risk factor for cancer development in LS (odds ratio: 34.0, 95% CI: 1.4-807.4). In conclusion, DNA methylation testing and p53 IHC show strong potential as prognostic biomarkers for the identification of LS patients at high risk of progression to cancer.

Stratification of Barrett's esophagus surveillance based on p53 immunohistochemistry: a cost-effectiveness analysis by an international collaborative group.

BACKGROUND: Surveillance of nondysplastic Barrett's esophagus (NDBE) is recommended to identify progression to dysplasia; however, the most cost-effective strategy remains unclear. Mutation of TP53 or aberrant expression of p53 have been associated with the development of dysplasia in BE. We sought to determine if surveillance intervals for BE could be stratified based on p53 expression. METHODS: A Markov model was developed for NDBE. Patients with NDBE underwent p53 immunohistochemistry (IHC) and those with abnormal p53 expression underwent surveillance endoscopy at 1 year, while patients with normal p53 expression underwent surveillance in 3 years. Patients with dysplasia underwent endoscopic therapy and surveillance. RESULTS: On base-case analysis, the strategy of stratifying surveillance based on abnormal p53 IHC was cost-effective relative to conventional surveillance and a natural history model, with an incremental cost-effectiveness ratio (ICER) of $8258 for p53 IHC-based surveillance. Both the conventional and p53-stratified surveillance strategies dominated the natural history model. On probabilistic sensitivity analysis, the p53 IHC strategy ($28 652; 16.78 quality-adjusted life years [QALYs]) was more cost-effective than conventional surveillance ($25 679; 16.17 QALYs) with a net monetary benefit of $306 873 compared with conventional surveillance ($297 642), with an ICER <$50 000 in 96% of iterations. The p53-stratification strategy was associated with a 14% reduction in the overall endoscopy burden and a 59% increase in dysplasia detection. CONCLUSION: A surveillance strategy for BE based on abnormal p53 IHC is cost-effective relative to a conventional surveillance strategy and is likely to be associated with higher rates of dysplasia diagnosis.

Characteristics and Prognosis of Sporadic Neoplasias Detected in Patients with Ulcerative Colitis.

INTRODUCTION: Patients with ulcerative colitis (UC) develop not only UC-associated neoplasias but also sporadic neoplasias (SNs). However, few studies have described the characteristics of SNs in patients with UC. Therefore, this study aimed to evaluate the clinical features and prognosis of SNs in patients with UC. METHODS: A total of 141 SNs in 59 patients with UC, detected by surveillance colonoscopy at Hiroshima University Hospital between January 1999 and December 2021, were included. SNs were diagnosed based on their location, endoscopic features, and histopathologic findings along with immunohistochemical staining for Ki67 and p53. RESULTS: Of the SNs, 91.5% were diagnosed as adenoma and 8.5% were diagnosed as carcinoma (Tis carcinoma, 3.5%; T1 carcinoma, 5.0%). 61.0% of the SNs were located in the right colon, 31.2% were located in the left colon, and 7.8% were located in the rectum. When classified based on the site of the lesion, 70.9% of SNs occurred outside and 29.1% within the affected area. Of all SNs included, 95.7% were endoscopically resected and 4.3% were surgically resected. Among the 59 patients included, synchronous SNs occurred in 23.7% and metachronous multiple SNs occurred in 40.7% during surveillance. The 5-year cumulative incidence of metachronous multiple SNs was higher in patients with synchronous multiple SNs (54.2%) than in those without synchronous multiple SNs (46.4%). CONCLUSION: Patients with UC with synchronous multiple SNs are at a higher risk of developing metachronous multiple SNs and may require a closer follow-up by total colonoscopy than patients without synchronous SNs.

[Precancers of the oral mucosa: clinic, diagnostics]. / Predraki slizistoi obolochki rta: klinika i diagnostika.

OBJECTIVE: The aim of the study. Improving the efficiency of diagnosis and detailing the features of the clinic of «potentially malignant¼ diseases of the oral mucosa. MATERIALS AND METHODS: Clinical and laboratory examination of 124 patients of the department of oral mucosa diseases aged 35 to 80 years, among whom there were 75 women and 49 men, with diseases such as erythroplakia - 12 patients, verrucous leukoplakia - 52 patients, erosive form of leukoplakia - 35 patients, cheilitis Manganotti - 25 patients. Histological and immunohistochemical methods of investigation were used as diagnostics. To assess the proliferative activity of epithelial cells, the determination of the Ki-67 index was used. The synthesis of keratin 15 (K15) in epithelial layers was determined as a diagnostic criterion for the severity of neoplasia. The expression of human papillomavirus type 16 (HPV 16) antigens and p16INK4a protein in epithelial cells was studied, as well as the expression of p53 protein. RESULTS: A high prevalence of p53 mutations was observed in patients with erythroplakia. In leukoplakia, the expression of the Ki-67 protein was detected in the cell nuclei in both the basal and parabasal layers of the multilayer squamous epithelium, in 77% of cases, the expression of the p16INK4a protein in the epithelial nuclei with varying degrees of dysplastic changes was noted, and a positive reaction to HPV16 was also observed in the cell nuclei and cytoplasm of epithelial cells in the basal, parabasal and spiny epithelial layers. The appearance of K15 in the cytoplasm of cells above the basal layer with abrasive precancerous cheilitis was found in 48% of cases. CONCLUSION: To diagnose early manifestations of neoplastic processes in «potentially malignant¼ diseases of the oral mucosa, it is necessary to use both classical histological and immunohistochemical methods of investigation with various markers.

CMTM6 recruits T cells within the endocervical adenocarcinoma microenvironment and suppresses cell proliferation via the p53 pathway.

Endocervical adenocarcinoma (ECA), harboring poor prognosis, is divided into human papilloma virus (HPV)-associated adenocarcinoma (HPVA) and non-HPVA (NHPVA), each consisting of a heterogeneous immune microenvironment. We aim to examine the effect of CKLF-like MARVEL transmembrane domain 6 (CMTM6), a key regulator of PD-L1, on ECA. Immunohistochemistry and RNA-sequencing (RNA-seq) were used to detect CMTM6, Programmed death ligand 1 (PD-L1), and immune cells biomarkers levels in tumors. RT-qPCR and Western Blotting were used to detect the mRNA and protein level changed in cells. The expression of CMTM6 in ECA is upregulated compared to cervical squamous cell carcinoma tissues. More infiltrating T cells were observed in CMTM6high ECA tissues, especially in CMTM6high HPVA. Higher expression of CMTM6 is associated with a higher rate of infiltrating CD8+ T cells in HPVA, but not in NHPVA. ECA patients were divided into three groups according to the co-expression status of CMTM6 and PD-L1(CPS) . Patients with CMTM6high /PD-L1(CPS+) had the longest OS and DFS, especially in NHPVA patients. Moreover, knock down of CMTM6 promotes ECA cell proliferation via the p53 pathway. CMTM6 recruits T cells, suppresses ECA cell proliferation via the p53 pathway and can be used as a novel prognostic indicator for ECA patients.

Defining an abnormal p53 immunohistochemical stain in Barrett's oesophagus-related dysplasia: a single-positive crypt is a sensitive and specific marker of dysplasia.

AIMS: p53 is an independent risk stratification marker in Barrett's oesophagus (BE), but no universally accepted definition exists for abnormal p53 staining. Herein, we assess p53 stains in two cohorts to: (1) define abnormal p53 staining in BE-related dysplasia (BERD) and (2) assess the specificity and sensitivity of this cut-point for the diagnosis of dysplasia. METHODS: Cohort 1 (n = 313) included (1) dysplastic BE biopsies, (2) prior non-dysplastic BE (NDBE) biopsies from the same patients and (3) NDBE biopsies from patients who never progressed to dysplasia. Cohort 2 (n = 191) consisted of BE biopsies in which p53 staining aided in diagnosing dysplasia. Automated p53 staining quantification was performed on cohort 1. A semiquantitative p53 analysis, performed on both cohorts, included: (1) number of strongly positive glands, (2) strong glandular surface staining, (3) percentage of strongly positive glands and (4) null phenotype. RESULTS: NDBE biopsies from cohort 1 patients who progressed to dysplasia were more likely to show p53 positivity than non-progressors (16.9 versus 0.6%) (P = 0.0001). The optimal quantitative cut-point for distinguishing dysplastic from never-dysplasia biopsies was 10 strongly positive cells. By semiquantitative analysis, a single strongly p53-positive gland distinguished dysplastic from never-dysplasia BE (sensitivity 98.6%, specificity 99.4%). The semiquantitative and quantitative analyses correlated (P = 0.0001). In cohort 2, the sensitivity and specificity for BERD of ≥ 1 strongly positive p53 gland were 86.0 and 88.6%. CONCLUSIONS: A single strongly positive p53 gland is sensitive and specific for BERD. Automated p53 analysis may reduce subjectivity associated with the diagnosis of BERD.

Human papillomavirus and p53 status define three types of vulvar squamous cell carcinomas with distinct clinical, pathological, and prognostic features.

INTRODUCTION: Based on their etiological relationship with human papillomavirus (HPV), the 2020 WHO classification has divided vulvar squamous cell carcinomas (VSCC) into two distinct types, HPV-associated and HPV-independent, and HPV-independent tumours have recently been divided according to p53 status. Nevertheless, the clinical and prognostic significance of this classification has not been clearly established. We analysed the differential clinical, pathological, and behavioural characteristics of these three types of VSCC in a large series of patients. METHODS AND RESULTS: VSCC samples from patients who underwent primary surgery at the Hospital Clinic of Barcelona, Spain, during a 47-year period (January 1975 to January 2022) were analysed (n = 190). HPV detection, p16, and p53 immunohistochemical staining were evaluated. We also analysed recurrence-free survival (RFS) and disease-specific survival (DSS). Thirty-three tumours (17.4%) were HPV-associated and 157 (82.6%) HPV-independent. Of these, 20 showed normal and 137 abnormal p53 expression. The two types of HPV-independent tumours showed worse RFS in the multivariate analysis (hazard ratio [HR] = 3.63; P = 0.023 for the HPV-independent p53 normal VSCC and HR = 2.78; P = 0.028 for the HPV-independent p53 abnormal VSCC). Although the differences were not significant, HPV-independent VSCC had worse DSS than HPV-associated VSCC. Although patients with HPV-independent p53 normal tumours had worse RFS than patients with HPV-independent p53 abnormal tumours, the DSS was better for the former group. Only advanced FIGO stage was associated with worse DSS in multivariate analysis (HR = 2.83; P = 0.010). CONCLUSION: The association of HPV and p53 status have prognostic implications, reinforcing a three-tier molecular classification of VSCC (HPV-associated VSCC, HPV-independent VSCC with normal p53, HPV-independent VSCC with abnormal p53).

p53 drives a transcriptional program that elicits a non-cell-autonomous response and alters cell state in vivo.

Cell stress and DNA damage activate the tumor suppressor p53, triggering transcriptional activation of a myriad of target genes. The molecular, morphological, and physiological consequences of this activation remain poorly understood in vivo. We activated a p53 transcriptional program in mice by deletion of Mdm2, a gene that encodes the major p53 inhibitor. By overlaying tissue-specific RNA-sequencing data from pancreas, small intestine, ovary, kidney, and heart with existing p53 chromatin immunoprecipitation (ChIP) sequencing, we identified a large repertoire of tissue-specific p53 genes and a common p53 transcriptional signature of seven genes, which included Mdm2 but not p21 Global p53 activation caused a metaplastic phenotype in the pancreas that was missing in mice with acinar-specific p53 activation, suggesting non-cell-autonomous effects. The p53 cellular response at single-cell resolution in the intestine altered transcriptional cell state, leading to a proximal enterocyte population enriched for genes within oxidative phosphorylation pathways. In addition, a population of active CD8+ T cells was recruited. Combined, this study provides a comprehensive profile of the p53 transcriptional response in vivo, revealing both tissue-specific transcriptomes and a unique signature, which were integrated to induce both cell-autonomous and non-cell-autonomous responses and transcriptional plasticity.

Mass Spectrometry Proteomic Analysis of Four p53 Patterns in Differentiated Vulvar Intraepithelial Neoplasia.

OBJECTIVE: The histopathologic diagnostic criteria of differentiated vulvar intraepithelial neoplasia (dVIN), the precursor of human papillomavirus-independent squamous cell carcinoma, are basal atypia, a negative or non-block-positive p16, and a supportive p53 immunohistochemistry (IHC). Several different patterns of supportive p53 IHC have been described. This study aims to determine the relationship between p53 IHC patterns and mass spectrometry analysis of cellular proteins in dVIN. METHODS: Four patterns of p53 IHC were studied: overexpression, cytoplasmic, wild type, and intermediate expression between wild type and overexpression. For each pattern, tissue samples of 4 examples were subjected to mass spectrometry. RESULTS: The protein profile within each p53 IHC pattern shared common features. Each of the 4 p53 patterns had a distinguishable protein profile when compared with the other 3 patterns. CONCLUSIONS: The distinguishable protein profiles in different p53 IHC patterns suggest diverse mechanisms of TP53 dysfunction. Subtyping dVIN by p53 IHC is worthy of further study because varied protein expression profiles may translate into different clinical behavior.

p53 null phenotype is a "positive result" in urothelial carcinoma in situ.

The concept of a "p53 null phenotype" (complete loss of staining) is well-recognized in the gynecologic pathology literature, implicitly reflecting that this staining pattern represents a TP53 mutation. However, in the genitourinary pathology literature, a p53 null phenotype has only been addressed regarding the prognosis of invasive urothelial carcinoma, and not as a diagnostic biomarker for urothelial carcinoma in situ (CIS). Herein, 25 cases of urothelial carcinoma in situ [diagnoses made on hematoxylin and eosin (H&E) stained sections] showing null pattern p53 staining were retrieved from 22 different patients (16 males and 6 females, age range 52-85 years; average 69.6 years), most commonly showing large cell pleomorphic pattern morphology. One representative tissue block per case was selected for next-generation DNA sequencing (NGS). All 21 cases (100%) passing quality control for NGS showed at least 1 TP53 mutation (majority nonsense or frameshift mutations), including 3 cases with 2 mutations and 3 cases with 3 mutations. Three patients with multiple available samples harbored 1 or more shared TP53 mutations at 2 different time points, indicating clonality of the temporally distinct lesions. Additionally, 2 patients had an additional unique TP53 mutation at a later time point, suggesting intratumoral heterogeneity and/or temporal clonal evolution. While urothelial CIS remains an H&E diagnosis in most cases, a p53 immunostain may be useful in a subset of challenging cases. This study demonstrates that a p53 null phenotype represents an aberrant result in urothelial CIS with supportive molecular analysis showing a previously unknown level of complexity for TP53 mutations among these noninvasive lesions. Adequate recognition of the p53 null phenotype as a "biologically supportive result", similar to strong and diffuse staining with p53, is important and may warrant a formal consensus statement for recommended p53 reporting (i.e., "wild type" versus "aberrant or mutant").

Molecular characterization of pleomorphic mesothelioma: a multi-institutional study.

The molecular alterations of pleomorphic mesotheliomas are largely unknown. In the present study, we performed whole-exome sequencing (WES) on 24 pleomorphic mesotheliomas in order to better characterize the molecular profile of this rare histologic variant. BAP1 protein expression and CDKN2A deletion by FISH were also evaluated. Significantly mutated genes included BAP1 (35%), NF2 (13%), LATS2 (8%), TP53 (5%), and LATS1 (3%). BAP1 alterations most frequently co-occurred with deletions of chromosomes 4, 9, and 13. Other important genetic alterations in pleomorphic mesotheliomas included truncating mutations in NF2 (3 of 24; 12.5%), LATS2 (2 of 24; 8%), TP53 (1 of 24; 4%), and PBRM1 (1 of 24; 4%). Focal losses of chromosome 9p21 were most common copy number alterations (11 of 24 cases; 46%), and were assessed by WES and targeted FISH. The second most common were deletions of chromosome 4 (8 of 24; 33% pleomorphic mesotheliomas). Three cases of pleomorphic mesothelioma did not show any mutations, copy number alterations, or LOH. This first WES analysis of pleomorphic mesotheliomas did not identify novel or unique mutations. In contrast to transitional mesothelioma that was reclassified as sarcomatoid variant based on transcriptome data, pleomorphic mesotheliomas are molecularly heterogeneous and therefore their reclassification into single subtype is more difficult.

Correlation of p53 immunohistochemistry with TP53 mutational status and overall survival in newly diagnosed acute myeloid leukaemia.

AIMS: TP53-mutated acute myeloid leukaemia (AML) is associated with an adverse prognosis and poor response to traditional chemotherapy regimens. Next-generation sequencing (NGS) is considered the gold standard method to determine TP53-mutational status; however, molecular assays are costly and time-consuming. In contrast, immunohistochemistry (IHC) can be performed within 1 day of biopsy. We sought to determine an optimal threshold of staining with p53 IHC to predict TP53-mutational status. METHODS AND RESULTS: We identified 142 consecutive patients with newly diagnosed AML with concurrent NGS analysis diagnosed between 2019 and 2020. All cases were stained for p53 IHC and images were scored for the percent of strongly stained p53+ cells by a combination of manual counting and image analysis. We then correlated percent positive staining with mutational status and clinical outcomes. We determined that a threshold of ≥7% strongly stained cells by p53 IHC correlated with the presence of a TP53 mutation with a sensitivity of 67%, specificity of 100%, positive predictive value of 100% and negative predictive value of 90%. TP53 mutation and the presence of ≥7% staining by IHC were associated with shorter overall survival by univariate analysis (P < 0.01). CONCLUSION: If the limitations of this study are carefully considered, our findings suggest that p53 protein expression as evaluated by IHC could be used to rapidly predict TP53-mutational status with high specificity and assist in risk stratification in newly diagnosed AML.

Serous tubal intra-epithelial carcinoma: what do we really know at this point?

Serous tubal intra-epithelial carcinoma (STIC) is the earliest morphologically recognisable step in the development of invasive high-grade serous carcinoma of the fallopian tube. Lesions occurring prior to STIC within the carcinogenic sequence for the pathogenesis of invasive high-grade serous carcinoma include the p53 signature and secretory cell outgrowth (SCOUT). Variable histological criteria have been used for diagnosing STIC, but a combination of morphology and immunohistochemistry for p53/Ki-67 improves interobserver agreement. Half of all carcinomas identified in risk-reducing salpingo-oophorectomy specimens are in the form of STIC; however, STIC also may be incidentally found on occasion in specimens from women at low or average risk of ovarian/tubal/peritoneal carcinoma. TP53 mutation is the earliest known DNA sequence alteration in STIC and almost all invasive high-grade serous carcinomas of the ovary and peritoneum. Data on the clinical behaviour of STIC are limited. While the short-term follow-up in the prior literature suggests a low risk of malignant progression, a more recent meta-analysis indicates a 10-year risk of 28%. STIC probably should be best regarded as a lesion with uncertain malignant potential at present, and future molecular analysis will help to classify those with higher risk of dissemination. This review provides an update on the current knowledge of STIC and related issues.

PLAC8 promotes the autophagic activity and improves the growth priority of human trophoblast cells.

Autophagy plays an important role in the normal development and function of trophoblast cells and is precisely regulated during pregnancy. Dysregulated autophagy contributes to the abnormal proliferation of trophoblasts, which is closely related to the occurrence of pregnancy-related diseases. Placenta specific 8 (PLAC8, Onzin) is a multifaceted protein proven to promote autophagy and potentiate various tumor progression. Its role in trophoblasts remains elusive. In our present study, PLAC8 expression was detected in tissues of first-trimester placentas (n = 5), term placentas (n = 5), choriocarcinoma (n = 5), and placental site trophoblastic tumor (n = 5). PLAC8 expression was increased in gestational neoplasms compared with normal pregnancies. mCherry-EGFP-LC3B reporter and transmission electron microscopy confirmed PLAC8 promoted the autophagic flux of human trophoblast cells. Both gain-of-function and loss-of-function experiments demonstrated PLAC8-regulated autophagy-related genes, including ATG5, ATG12, and Beclin-1. In addition, our data showed that PLAC8 co-localized with p53 and promoted its degradation, and p53 re-expression partially abrogated the PLAC8-induced autophagy activity. Furthermore, the overexpression of PLAC8 promoted cell viability and proliferation, acting as a protective mechanism of trophoblasts against the cytotoxicity of etoposide (VP-16). Such a phenomenon was effectively abrogated by autophagy inhibitors 3-methyladenine (3-MA) and chloroquine (CQ). In conclusion, PLAC8-induced autophagy to promote the proliferation of trophoblasts. This study provided insights into the mechanism of PLAC8-induced autophagy in trophoblasts, which is significant for a wide range of gestational diseases and may contribute to developing novel treatment strategies for trophoblastic diseases.

Comparative Immunohistochemical Analysis of p53 and Alpha-SMA in Ameloblastoma, AOT and OKC.

OBJECTIVES: Ameloblastoma is a benign but highly infiltrative tumour, a behaviour that is lacking in adenomatoid odontogenic tumour but partly shared by the odontogenic keratocyst which possesses a unique intrinsic growth potential with marked ability for destroying bone and a high tendency recurrence. High frequency of stromal myofibroblasts (assessed with alpha smooth muscle actin (α-SMA) correlates with aggressive behaviour while p53-cell cycle regulation system is critical in odontogenic tumours with immunoreactivity signifying prognostic status. This study aims to determine and compare the immunoreactivity of these selected tumours to p53 and α-SMA in order to establish if a relationship exists between the frequency and pattern of distribution of myofibroblasts and the behaviour of these lesions. MATERIALS AND METHODS: 69 blocks of ameloblastoma, and 23 each of adenomatoid odontogenic tumor (AOT), and odontogenic keratocyst (OKC/KCOT) were retrieved. Immunohistochemistry technique was applied for evaluation of these two markers staining with primary antibodies to p53 and -SMA and the frequency and pattern of distribution of myofibroblasts and immunoreactivity to p53 analysed and compared using ANOVA. p was set at <0.05. RESULTS AND CONCLUSION: Immunoreactivity to p53 and α-SMA was highest in ameloblastoma (solid compared to unicystic) with highest mean positive cells to α-SMA (29.7±20.1) and p53 (28.3±24.5) in plexiform ameloblastoma. This suggests that ameloblastoma was the most aggressive of tumours studied. Different pharmacological agents that can regulate stromal MF are useful aids to decrease the need for radical surgery in extensive and aggressive odontogenic tumours.

ABSTRAIT OBJECTIFS: L'améloblastome est bénin mais untumeur mes infiltratif, un comportement qui fait défaut dans la tumeur odontogénique adénomatoïde mais en partie partagé par le kératocyste odontogène qui possède un potentiel de croissance intrinsèque unique avec une capacité marquée de destructionet une récidive à forte tendance. Haute fréquence de stromalmyofibroblastes (évalués avec de l'actine musculaire alpha lisse (α-SMA) est en corrélation avec un comportement agressif lors de la régulation du cycle des cellules p53 est essentiel dans les tumeurs odontogènes immunoréactives signifiant le statut pronostique. Cette étude vise à déterminer et comparer activité l'immunoré de ces tumeurs sélectionnées à p53 et α-SMA afin d'établir s'il existe une relation entre le fréquence et schéma de distribution des myofibroblastes et de la comportement de ces lésions. MATÉRIAUX ET MÉTHODES: 69 blocs d'améloblastome, et 23 chacun de tumeur odontogénique adénomatoïde (AOT) et odontogènedes kératocystes (OKC/KCOT) ont été récupérés. Immunohistochimiela technique a été appliquée pour l'évaluation de ces deux marqueurs de coloration avec des anticorps primaires dirigés contre p53 et α-SMA et la fréquence et schéma de distribution des myofibroblastes et de l'immunoréactivité àp53 analysé et comparé à l'aide de l'ANOVA. p a été fixé à <0,05. RÉSULTATS ET CONCLUSION: Immuno réactivité à p53 et α-SMA était la plus élevée dans l'améloblastome (solide par rapport α-SMA (29,7±20,1) et p53(28,3±24,5) dans l'améloblastome plexiforme. Cela suggère que L'améloblastome était la tumeur la plus agressive étudiée. Les agents pharmacologiques différentes peuvent réguler la MF stromale sont des aides utiles pour diminuer le besoin de chirurgie radicale en cas de chirurgie étendue et agressive tumeurs odontogènes. Mots-clés: Améloblastome, AOT, OKC/KCOT, p53, α-SMA, myofibroblastes, tumeurs odontogènes, immunoréactivité.

Mural nodules in mucinous ovarian tumors represent a morphologic spectrum of clonal neoplasms: a morphologic, immunohistochemical, and molecular analysis of 13 cases.

Mucinous ovarian tumors rarely harbor mural nodules, which have historically been classified as sarcoma-like, anaplastic carcinomatous, or sarcomatous on the basis of predominant morphologic features. The molecular relationship between mural nodules and associated mucinous ovarian tumors remains poorly characterized, as does the molecular pathogenesis of these mural nodules. Thus, we analyzed the morphological, immunohistochemical, and genetic features of 13 mucinous ovarian tumors and associated mural nodule(s). Three harbored sarcoma-like mural nodules and ten contained anaplastic carcinomatous nodules, including 1 tumor with spatially discrete anaplastic carcinomatous and sarcomatous nodules. Twelve of 13 cases showed genetic evidence of clonality between the mural nodule(s) and associated mucinous ovarian tumor, including all three tumors with sarcoma-like morphology. Mural nodules were genetically identical in the five cases in which there were multiple discrete mural nodules that were sequenced separately. MTAP and p53 immunohistochemistry confirmed the distribution of neoplastic cells in a subset of sarcoma-like and anaplastic carcinomatous nodules. No single recurrent genetic alteration was associated with mural nodule development. No recurrent genetic differences were identified between mural nodules with sarcoma-like, anaplastic carcinomatous, and sarcomatous morphology. Of 11 patients with clinical follow-up, three died of disease 3, 8, and 9 months after diagnosis, but no recurrent genetic events were associated with poor outcome. These molecular data suggest that sarcoma-like, anaplastic carcinomatous, and sarcomatous nodules represent a morphologic spectrum of clonal neoplasms arising in mucinous ovarian tumors rather than three discrete biological entities.

Histopathologic features of breast cancer in Li-Fraumeni syndrome.

Breast cancer is the most common malignancy in female patients with Li-Fraumeni syndrome (LFS), a rare autosomal dominant hereditary syndrome characterized by germline TP53 mutations. Recent studies have shown that the majority of these tumors are estrogen receptor (ER) positive with frequent HER2 co-expression. However, the morphologic features of these tumors have not been as well studied as other germline-associated breast cancers. We evaluated the pathologic features of 27 invasive and in situ carcinomas from patients with known germline TP53 mutations collected through the Li-Fraumeni Consortium. Overall, 60% of cases were HER2 positive and 44% showed ER co-expression. Most DCIS was high nuclear grade with central necrosis and associated periductal fibrosis and lymphocytic response. Invasive carcinomas were mostly of ductal type (NOS), modified Scarff-Bloom-Richardson (mSBR) high grade, with marked nuclear atypia and high mitotic rate. Prominent tumor infiltrating lymphocytes, syncytial growth pattern, or pushing borders were not seen in these tumors. High p53 IHC expression was seen in tumors from individuals with germline TP53 missense mutations whereas little or no protein expression (<1% nuclear expression, null pattern) was seen in tumors from carriers of non-missense mutations. In this study, we report in detail the morphologic features of invasive and in situ carcinomas in LFS. We found that these tumors share features with cancers harboring somatic TP53 mutations but are distinct from BRCA-associated breast cancers.

Oropharyngeal squamous cell carcinoma: p16/p53 immunohistochemistry as a strong predictor of HPV tumour status.

AIMS: Oropharyngeal squamous cell carcinomas (OPSCC) related to human papillomavirus (HPV) infection have a better prognosis than those without HPV infection. Although p16INK4a overexpression is used as a surrogate marker for HPV infection, 5-20% of p16-positive OPSCC are described as being unrelated to HPV infection, with worse overall survival compared to OPSCC-related HPV. There is therefore a risk of undertreating a proportion of OPSCC patients falsely considered to be HPV-driven because of p16 positivity. TP53 mutations are highly prevalent in OPSCC driven by mutagens in tobacco and alcohol. We describe herein a combined p16/p53 algorithm to predict HPV tumour status in OPSCC. METHODS AND RESULTS: A total of 110 OPSCC were identified in the database of the pathology department and were studied using p16 and p53 immunohistochemistry. For p16-positive or p16-negative/wild-type patterns-p53 (WT-p53) cases (n = 63), DNA in-situ hybridisation for high-risk HPV was performed, and if negative the HPV status was controlled by HPV DNA polymerase chain reaction (PCR) (n = 19). A significant association between TP53 mutation and pattern of p53 expression was found (WT-p53, seven of 16, P < 0.001). The p16-positive/WT-p53 was significantly associated with HPV+ tumour status (p16-positive/WT-p53, 50 of 110, P < 0.001). Interestingly, a subset of p16-positive OPSCC was unrelated to HPV (13.5%, eight of 59), and showed mutant-type staining of p53 expression. CONCLUSIONS: The p16 protein immunopositivity in conjunction with the mutant-type pattern of p53 staining helped to reclassify a subset of p16-positive OPSCC as OPSCC-unrelated HPV. This approach could be routinely applied by pathologists involved in the management of OPSCC, because of their potential therapeutic implications.

Comparison of p53 immunohistochemical staining in differentiated vulvar intraepithelial neoplasia (dVIN) with that in inflammatory dermatoses and benign squamous lesions in the vulva.

AIMS: Differentiated vulvar intraepithelial neoplasia (dVIN), the precursor lesion to human papillomavirus-independent vulvar squamous cell carcinoma (VSCC), can be difficult to distinguish from vulvar inflammatory dermatoses. Our goal was to determine if p53 could be a useful biomarker for dVIN, by characterizing p53 percentage, intensity and patterns of staining in dVIN and its histological mimics. METHODS AND RESULTS: We studied p53 immunohistochemical staining patterns in 16 dVIN cases and 46 vulvar non-neoplastic squamous lesions [12 lichen sclerosus (LS); seven lichen simplex chronicus; three lichen planus (LP); six psoriasis; 13 spongiotic dermatitis (SPO); and five candidiasis]. dVIN cases were adjacent to a p16-negative invasive VSCC in resection specimens. All dVIN cases showed null-type or moderate to strong uniform p53 staining in >70% of basal cells, with moderate to strong continuous parabasal staining extending to two-thirds of the epidermis. This was in contrast to weak or weak to moderate patchy p53 staining in the majority of other lesions. Moderate to strong and increased basal p53 staining (≥70%) was also observed in a subset of LS cases (5/12, 42%), LP cases (1/3, 33%), and SPO cases (36%, 4/11); however, in all categories, this was limited to the basal layer, and any staining in the parabasal layers was patchy. CONCLUSION: Strong and uniform p53 staining of basal cells, extending into the parabasal layers, and a complete absence of staining (null type) is useful in distinguishing dVIN from other mimics in the vulva. p53 staining of lesser intensity or quantity, particularly basal overexpression only, overlaps with that in vulvar inflammatory lesions.