Improved production of class I phosphatidylinositol 4,5-bisphosphate 3-kinase.

Phosphatidylinositol 4,5-bisphosphate 3-kinases (PI3K) are a family of kinases whose activity affects pathways needed for basic cell functions. As a result, PI3K is one of the most mutated genes in all human cancers and serves as an ideal therapeutic target for cancer treatment. Expanding on work done by other groups we improved protein yield to produce stable and pure protein using a variety of modifications including improved solubility tag, novel expression modalities, and optimized purification protocol and buffer. By these means, we achieved a 40-fold increase in yield for p110α/p85α and a 3-fold increase in p110α. We also used these protocols to produce comparable constructs of the ß and δ isoforms of PI3K. Increased yield enhanced the efficiency of our downstream high throughput drug discovery efforts on the PIK3 family of kinases.

Alpelisib and Immunotherapy: A Promising Combination for Recurrent and Metastatic Squamous Cell Carcinoma of the Head and Neck.

BACKGROUND: Recurrent squamous cell carcinoma (SCC) of the head and neck (SCCHN) remains a formidable clinical challenge despite available treatments. The phosphatidylinositol 3-kinase (PI3K) pathway has been identified as a potential therapeutic target, and alpelisib, a selective PI3Kα inhibitor, has demonstrated efficacy in certain malignancies. Combining this targeted therapy with immunotherapy has been suggested in previous studies as a promising strategy to bolster the immune response against cancer. CASES: A 69-year-old woman with locoregional recurrence of PIK3CA-mutated SCC of the left maxilla and cervical nodal metastases. Several chemotherapeutic regimens, including cisplatin, docetaxel, 5FU, chemoradiotherapy, and mono-immunotherapy, resulted in disease progression. Alpelisib combined with pembrolizumab led to a sustained response for 9 months. A 58-year-old man with recurrent metastatic PIK3CA-mutated SCC of the oropharynx, involving the left lung, hilar, and mediastinal lymph nodes. Despite prior palliative radiation and platinum-based chemotherapy with pembrolizumab and cetuximab, treatment with alpelisib and nivolumab resulted in a partial response. Severe hyperglycemia and rash led to treatment discontinuation. CONCLUSION: Our findings highlight the potential of this innovative therapeutic combination, suggesting a need for further investigations in this setting.

Mutational analysis differentiating sporadic carcinomas from colitis-associated colorectal carcinomas.

BACKGROUND: Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) that is associated with increased risk of developing colitis-associated carcinoma (CAC). The genetic profile of CACs is fairly similar to the sporadic colorectal carcinomas (sCRCs), although showing certain differences in the timing and sequence of alterations that contribute to carcinogenesis. Also, both cancer types typically show a strong histological resemblance, which complicates the pathologists' diagnosis. Due to the different clinical consequences, it is of utmost importance to categorize the corresponding cancer type correctly. METHODS: In this study, we determined the mutation profiles of 64 CACs and sCRCs in the hotspot regions of 50 cancer-associated genes and compared them to 29 controls to identify genetic gene variants that can facilitate the pathologists' diagnosis. Pearson Chi-Square or Fisher's exact tests were used for statistical analyses. RESULTS: We found that sCRCs tend to mutate more frequently in APC and PIK3CA genes than CACs and that mainly males were affected. Our CAC cohort identified the KRAS G12D mutation as group-specific variant that was not detected in the sCRCs. When separating conventional from non-conventional CACs, it was discovered that the conventional type shows significantly more mutations for ATM. CONCLUSIONS: Taken together, our data highlights genetic differences between sCRC and CAC and enables the possibility to utilize specific gene alterations to support the pathologist's diagnosis.

Ultrasensitive detection of circulating tumor DNA using a CRISPR/Cas9 nickase-driven 3D DNA walker based on a COF-AuNPs sensing platform.

A electrochemical biosensor was designed utilizing a CRISPR Cas9n-driven DNA walker combined with gold-nanosphere-like covalent organic frameworks (COFs-AuNPs) to detect breast cancer markers (PIK3CA E545K ctDNA). The DNA walker probe is activated only in the presence of circulating tumor deoxyribonucleic acid (ctDNA), binding to a support probe to form a double strand that is then specifically cleaved by the Cas9n/sgRNA complex. This cleavage produces numerous DNA fragments for signal amplification. The COF-AuNPs as electrode materials facilitate electronic transfer and provide additional active sites for the immobilization of nucleic acid probes. This setup achieves a detection limit of 1.76 aM, demonstrating high sensitivity. Additionally, Cas9n improves the specificity of the sensor, accurately distinguishing a pair of base-mismatched sequences, and reducing the occurrence of false positives. Overall, the sensor exhibits excellent selectivity, reproducibility, and potential for early diagnosis of breast cancer.

Pulmonary artery mass with PIK3CA mutation after orthotopic heart transplantation.

BACKGROUND: Patients can develop de novo malignancies following orthotopic heart transplantation. However, vascular tumors are not commonly described in this population. CASE PRESENTATION: We present a 69-year-old female with a history of orthotopic heart transplantation for chemotherapy-induced cardiomyopathy who developed an incidental pulmonary artery mass six years after her transplantation. Given concerns for malignancy, the patient underwent an operative excisional biopsy through a left anterior mini-thoracotomy with femoral artery and vein cannulation for cardiopulmonary bypass. The mass was determined to be a non-malignant vascular overgrowth with PIK3CA mutation. CONCLUSION: We present the case of an unusual pulmonary artery mass with PIK3CA mutation found in a post heart transplant patient. We were able to spare her the morbidity of a redo-sternotomy by excising the mass via a minimally invasive left anterior thoracotomy approach.

Detection of PIK3CA hotspot mutations in canine mammary tumors using droplet digital PCR: tissue validation and liquid biopsy feasibility.

Domestic dogs (Canis lupus familiaris) serve as valuable translational models for human cancer research due to their biological similarities. Canine mammary tumors (CMTs), frequently diagnosed in female dogs, share various characteristics with human breast cancers. This study investigates the PIK3CA (H1047R) mutation in CMTs using droplet digital PCR (ddPCR) and explores the potential of liquid biopsy for non-invasive detection. We analyzed 80 formalin-fixed, paraffin-embedded (FFPE) CMT tissue samples and compared ddPCR results with next-generation sequencing (NGS) data, achieving high concordance. Plasma and serum samples were also assessed for mutation concordance with tissue results. Our findings indicate a higher frequency of the PIK3CA (H1047R) mutations in benign and grade I malignant CMTs compared to more aggressive malignancies. The ddPCR assay demonstrated high sensitivity and specificity, with plasma testing showing 78.6% sensitivity and 87.5% specificity, and serum testing showing 66.7% sensitivity and 90.0% specificity. These results highlight the viability of liquid biopsy as a minimally invasive method for monitoring PIK3CA mutations in canine patients. The study suggests that liquid biopsy techniques hold significant promise for improving the early detection and monitoring of canine cancers, warranting further research to refine these methods and explore their applications in canine cancer diagnostics and treatment.

Defining the transcriptome of PIK3CA-altered cells in a human capillary malformation using single cell long-read sequencing.

PIK3CA-related overgrowth spectrum (PROS) disorders are caused by somatic mosaic variants that result in constitutive activation of the phosphatidylinositol-3-kinase/AKT/mTOR pathway. Promising responses to molecularly targeted therapy have been reported, although identification of an appropriate agent can be hampered by the mosaic nature and corresponding low variant allele frequency of the causal variant. Moreover, our understanding of the molecular consequences of these variants-for example how they affect gene expression profiles-remains limited. Here we describe in vitro expansion of a human capillary malformation followed by molecular characterization using exome sequencing, single cell gene expression, and targeted long-read single cell RNA-sequencing in a patient with clinical features consistent with Megalencephaly-Capillary Malformation Syndrome (MCAP, a PROS condition). These approaches identified a targetable PIK3CA variant with expression restricted to PAX3+ fibroblast and undifferentiated keratinocyte populations. This study highlights the innovative combination of next-generation single cell sequencing methods to better understand unique transcriptomic profiles and cell types associated with MCAP, revealing molecular intricacies of this genetic syndrome.

Inavolisib-Based Therapy in PIK3CA-Mutated Advanced Breast Cancer.

BACKGROUND: Inavolisib is a highly potent and selective inhibitor of the alpha isoform of the p110 catalytic subunit of the phosphatidylinositol 3-kinase complex (encoded by PIK3CA) that also promotes the degradation of mutated p110α. Inavolisib plus palbociclib-fulvestrant has shown synergistic activity in preclinical models and promising antitumor activity in early-phase trials. METHODS: In a phase 3, double-blind, randomized trial, we compared first-line inavolisib (at an oral dose of 9 mg once daily) plus palbociclib-fulvestrant (inavolisib group) with placebo plus palbociclib-fulvestrant (placebo group) in patients with PIK3CA-mutated, hormone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative locally advanced or metastatic breast cancer who had had relapse during or within 12 months after the completion of adjuvant endocrine therapy. The primary end point was progression-free survival as assessed by the investigator. RESULTS: A total of 161 patients were assigned to the inavolisib group and 164 to the placebo group; the median follow-up was 21.3 months and 21.5 months, respectively. The median progression-free survival was 15.0 months (95% confidence interval [CI], 11.3 to 20.5) in the inavolisib group and 7.3 months (95% CI, 5.6 to 9.3) in the placebo group (hazard ratio for disease progression or death, 0.43; 95% CI, 0.32 to 0.59; P<0.001). An objective response occurred in 58.4% of the patients in the inavolisib group and in 25.0% of those in the placebo group. The incidence of grade 3 or 4 neutropenia was 80.2% in the inavolisib group and 78.4% in the placebo group; grade 3 or 4 hyperglycemia, 5.6% and 0%, respectively; grade 3 or 4 stomatitis or mucosal inflammation, 5.6% and 0%; and grade 3 or 4 diarrhea, 3.7% and 0%. No grade 3 or 4 rash was observed. Discontinuation of any trial agent because of adverse events occurred in 6.8% of the patients in the inavolisib group and in 0.6% of those in the placebo group. CONCLUSIONS: In patients with PIK3CA-mutated, hormone receptor-positive, HER2-negative locally advanced or metastatic breast cancer, inavolisib plus palbociclib-fulvestrant led to significantly longer progression-free survival than placebo plus palbociclib-fulvestrant, with a greater incidence of toxic effects. The percentage of patients who discontinued any trial agent because of adverse events was low. (Funded by F. Hoffmann-La Roche; INAVO120 ClinicalTrials.gov number, NCT04191499.).

The genomic and transcriptomic landscape of metastastic urothelial cancer.

Metastatic urothelial carcinoma (mUC) is a lethal cancer, with limited therapeutic options. Large-scale studies in early settings provided critical insights into the genomic and transcriptomic characteristics of non-metastatic UC. The genomic landscape of mUC remains however unclear. Using Whole Exome (WES) and mRNA sequencing (RNA-seq) performed on metastatic biopsies from 111 patients, we show that driver genomic alterations from mUC were comparable to primary UC (TCGA data). APOBEC, platin, and HRD mutational signatures are the most prevalent in mUC, identified in 56%, 14%, and 9% of mUC samples, respectively. Molecular subtyping using consensus transcriptomic classification in mUC shows enrichment in neuroendocrine subtype. Paired samples analysis reveals subtype heterogeneity and temporal evolution. We identify potential therapeutic targets in 73% of mUC patients, of which FGFR3 (26%), ERBB2 (7%), TSC1 (7%), and PIK3CA (13%) are the most common. NECTIN4 and TACSTD2 are highly expressed regardless of molecular subtypes, FGFR3 alterations and sites of metastases.

Apolipoprotein-B mRNA-editing complex 3B could be a new potential therapeutic target in endometriosis.

This study investigated the correlation of Apolipoprotein-B mRNA-editing complex 3B (APOBEC3B) expression with hypoxia inducible factor 1α (HIF-1α), Kirsten rat sarcoma virus (KRAS) and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) in endometriosis patients, and the inhibitory effects of APOBEC3B knockdown in a human endometriotic cell line. Here, APOBEC3B, HIF-1α, KRAS, and PIK3CA were examined in patients with and without endometriosis using reverse transcription polymerase chain reaction (RT-PCR). The apoptosis, cell proliferation, invasion, migration, and biological function of APOBEC3B knockdown were explored in 12Z immortalized human endometriotic cell line. We observed APOBEC3B, HIF-1α, KRAS and PIK3CA expressions were significantly higher in endometriosis patients (p < 0.001, p < 0.001, p = 0.029, p = 0.001). Knockdown of APOBEC3B increased apoptosis, which was 28.03% and 22.27% higher than in mock and control siRNA samples, respectively. APOBEC3B knockdown also decreased PIK3CA expression and increased Caspase 8 expression, suggesting a potential role in the regulation of apoptosis. Furthermore, knockdown of APOBEC3B significantly inhibited cell proliferation, invasion, and migration compared to mock and control siRNA. (Cell proliferation: mock: p < 0.001 and control siRNA: p = 0.049. Cell invasion: mock: p < 0.001 and control siRNA: p = 0.029. Cell migration: mock: p = 0.004, and control siRNA: p = 0.014). In conclusion, this study suggests that APOBEC3B may be a new potential therapeutic target for endometriosis.

A single center experience on PI3K/AKT/MTOR signaling defects: Towards pathogenicity assessment for four novel defects.

BACKGROUND: Phosphoinositide 3 kinases (PI3K) are lipid kinases expressed in lymphocytes/myeloid cells. PI3K/AKT/mTOR signaling defects present with recurrent infections, autoimmunity, lymphoproliferation, and agammaglobulinemia. OBJECTIVE: To characterize the PI3K/AKT/mTOR pathway defects and perform pathway analyses to assess novel variant pathogenicity. METHODS: We included 12 patients (heterozygous PIK3CD (n = 9) and PIK3R1 (n = 1) (activated PI3K delta syndrome (APDS) with gain-of-function mutations) and homozygous PIK3R1 variant (n = 2)), performed clinical/laboratory/genetic evaluation, and flow cytometric PI3K/AKT/mTOR pathway analyses. RESULTS: Median age at onset of complaints was 17.5 months (3 months to 12 years) and at diagnosis was 15.7 years (2.5-37) in APDS. Median diagnostic delay was 12.9 years (1.6-27). Recurrent respiratory tract infections (90%), lymphoproliferation (70%), autoimmune/inflammatory findings (60%), and allergy (40%) were common in APDS. Recurrent viral infections were present in 4/10 and malignancy (non-Hodgkin lymphoma and testicular yolk sac tumor) was present in 2/10 in APDS. Low CD4+ T cells(5/8) with increased CD4+ effector memory (8/8) and CD4+ TEMRA cells (6/8) were present in the given number of APDS patients. We diagnosed tubulointerstitial nephritis, Langerhans cell histiocytosis, and late-onset congenital adrenal hyperplasia in APDS. Allergic findings, lymphoproliferation/malignancy, and high IgM were present in the APDS but not in PIK3R1 deficiency. Low IgM/IgG/CD19+ B cell counts were characteristic in patients with PIK3R1 homozygous loss-of function mutations. CONCLUSION: Differential diagnosis with combined immunodeficiency and diseases of immune dysregulation make molecular genetic analysis crucial for diagnosing mTOR pathway defects. It is easy to differentiate APDS and homozygous PIK3R1 defects with specific laboratory features. Additionally, mTOR pathway functional analysis is a definitive diagnostic and pathogenicity assessment tool for novel APDS mutations.

Constitutional Mutation of PIK3CA: A Variant of Cowden Syndrome?

We present a family in which four individuals have been identified with the same likely pathogenic genetic alteration in the PIK3CA gene at the germinal level; specifically, c.1145G>A p.(Arg382Lys) missense type. The index case patient was diagnosed with multinodular goiter and breast cancer at 61 years old. Among the other three carrier relatives: one has been diagnosed with serous cystadenoma of the ovary and a thyroid nodule with no radiological suspicion of malignancy; the other two present multinodular goiter. Additionally, a sister of three of the carriers suffered from an ovarian teratoma, follicular thyroid carcinoma on multinodular goiter, and high-grade serous ovarian carcinoma. No direct mutation study was performed on her as she had died due to ovarian carcinoma. This finding suggests that the PIK3CA gene should be considered in Cowden-like families when no other gene mutations have been found. Furthermore, this report contributes to characterization of the clinical phenotype caused by mutations in PIK3CA, which may be shared with other hereditary breast and ovarian cancer syndromes.

Case report on activated PI3K-delta syndrome.

BACKGROUND: Activated phosphoinositide 3-kinase delta syndrome (APDS) [OMIM 615513] is an inborn error of immunity with autosomal dominant inheritance caused by a pathogenic variant in the PIK3CD gene. The prevalence ratio of APDS is < 1: 1,000,000 newborns. The main clinical features of APDS are sinopulmonary infections, benign lymphoproliferation, autoinflammatory disease, and a major risk of lymphoid neoplasms. CLINICAL CASE: A 17-year-old female with a history of pneumonia at 9 months of age subsequently developed recurrent respiratory tract infections, bronchiectasis, perforated otitis media, unilateral tonsillar lymphoid hyperplasia, pansinusitis, recurrent oral candidiasis, and chronic rhinitis. Laboratory studies reported persistent leukopenia and lymphopenia, low CD4 lymphocyte subpopulation, and persistently elevated immunoglobulin M immunoglobulin studies with values up to 692 mg/dL. An inborn error of immunity next-generation sequencing and multiplex ligation-dependent probe amplification analysis detected a heterozygous pathogenic variant in the PIK3CD gene, compatible with APDS. Treatment with monthly injectable gamma globulin and prophylactic antibiotics was started, allowing better control of the infectious processes. CONCLUSION: This is the second case of APDS reported in Mexico in the literature. It is important to be aware of this condition to make a timely diagnosis, which requires a high clinical suspicion and immunological and genetic studies to provide adequate treatment and prevent complications.

INTRODUCCIÓN: El síndrome de la Fosfoinositida 3-cinasa delta activado (Activated Phosphoinositide 3-kinase δ síndrome, APDS) [OMIM 615513] es un error innato de la inmunidad con patrón de herencia autosómica dominante causada por una variante patogénica heterocigota del gen PIK3CD. Su prevalencia es < 1: 1,000,000 nacidos vivos. Las principales manifestaciones clínicas son infecciones sinopulmonares, linfoproliferación benigna, autoinmunidad y aumento del riesgo de malignización linfoide. CASO CLÍNICO: Femenino de 17 años de vida con antecedentes de neumonía a los 9 meses de edad, posteriormente infecciones de vías respiratorias recurrentes, bronquiectasias, otitis media perforada, hiperplasia linfoide de amigdala unilateral, pansinusitis, candidiasis oral recurrente y rinitis crónica. Los estudios de laboratorio reportaron leuco linfopenia persistente, subpoblación linfocitaria con CD4 baja y estudios de inmunoglobulinas con IgM persistentemente elevada con valor de hasta 692 mg/dl. Se realizó estudio molecular de secuenciación de siguiente generación (NGS por sus siglas en inglés Next-Generation Sequencing) y amplificación de sondas dependientes de ligandos múltiples (MLPA por sus siglas en inglés Multiplex Ligation-dependent Probe Amplification) dirigido a errores innatos de la inmunidad que detectó una variante patogénica en estado heterocigoto en el gen PIK3CD, compatible con APDS. Se inició tratamiento con gammaglobulina intravenosa mensual y antibiótico profiláctico, permitiendo mejor control de los procesos infecciosos. CONCLUSIONES: Este es el segundo caso reportado en la literatura de APDS en México, por lo que es importante su conocimiento para poder realizar un diagnóstico oportuno, para el cual se requiere una alta sospecha clínica, además de estudios inmunológicos y genéticos, con la finalidad de otorgar el tratamiento adecuado y prevenir complicaciones.

Determination of the frequency and distribution of APC, PIK3CA, and SMAD4 gene mutations in Ugandan patients with colorectal cancer.

Uganda is a developing low-income country with a low incidence of colorectal cancer, which is steadily increasing. Ugandan colorectal cancer (CRC) patients are young and present with advanced-stage disease. In our population, there is a scarcity of genetic oncological studies, therefore, we investigated the mutational status of CRC tissues, focusing in particular on the adenomatous polyposis coli (APC), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), and SMAD4 genes. Our objective was to determine whether there were any differences between other populations and Ugandan patients. We performed next-generation sequencing on the extracted DNA from formalin-fixed paraffin-embedded adenocarcinoma samples from 127 patients (mean (SD) age: 54.9 (16.0) years; male:female sex ratio: 1.2:1). Most tumours were located in the rectum 56 (44.1%), 14 (11%) tumours were high grade, and 96 (75.6%) were moderate grade CRC. Stage III + IV CRC tumours were found in 109 (85.8%) patients. We identified 48 variants of APC, including 9 novel APC mutations that were all pathogenic or deleterious. For PIK3CA, we found 19 variants, of which 9 were deleterious or pathogenic. Four PIK3CA novel pathogenic or deleterious variants were included (c.1397C > G, c.2399_2400insA, c.2621G > C, c.2632C > G). Three SMAD4 variants were reported, including two pathogenic or deleterious variants (c.1268G > T, c.556dupC) and one tolerant (c.563A > C) variant. One novel SMAD4 deleterious mutation (c.1268G > T) was reported. In conclusion, we provide clinicopathological information and new genetic variation data pertinent to CRC in Uganda.

Testing of rapid evaporative mass spectrometry for histological tissue classification and molecular diagnostics in a multi-site study.

BACKGROUND: While REIMS technology has successfully been demonstrated for the histological identification of ex-vivo breast tumor tissues, questions regarding the robustness of the approach and the possibility of tumor molecular diagnostics still remain unanswered. In the current study, we set out to determine whether it is possible to acquire cross-comparable REIMS datasets at multiple sites for the identification of breast tumors and subtypes. METHODS: A consortium of four sites with three of them having access to fresh surgical tissue samples performed tissue analysis using identical REIMS setups and protocols. Overall, 21 breast cancer specimens containing pathology-validated tumor and adipose tissues were analyzed and results were compared using uni- and multivariate statistics on normal, WT and PIK3CA mutant ductal carcinomas. RESULTS: Statistical analysis of data from standards showed significant differences between sites and individual users. However, the multivariate classification models created from breast cancer data elicited 97.1% and 98.6% correct classification for leave-one-site-out and leave-one-patient-out cross validation. Molecular subtypes represented by PIK3CA mutation gave consistent results across sites. CONCLUSIONS: The results clearly demonstrate the feasibility of creating and using global classification models for a REIMS-based margin assessment tool, supporting the clinical translatability of the approach.

PIK3CA mutational status in tissue and plasma as a prognostic biomarker in HR+/HER2- breast cancer.

INTRODUCTION: Hotspots (HS) mutations in the PIK3CA gene may lead to poorer oncological outcomes and endocrine resistance in advanced breast cancer (BC), but their prognostic role in early-stage disease remains controversial. The overall agreement within plasma and tissue methods has not been well explored. Our aim was to correlate tissue and plasma approaches and to analyze the prognostic impact of PIK3CA mutations (PIK3CAm) in HR+/HER2- BC. METHODS: A retrospective and unicentric analysis of PIK3CA mutational status in tissue and plasma samples by Cobas®PIK3CA Mutation Kit in patients with HR+/HER2- BC. RESULTS: We analyzed 225 samples from 161 patients with luminal BC. PIK3CA mutations were identified in 62 patients (38.5%), of which 39.6% were found in tissue and 11.8% in plasma. In advanced disease, plasma and tissue correlation rate was performed in 64 cases, with an overall agreement of 70.3%. Eighty patients were treated with CDK4/6 inhibitors + endocrine therapy. We observed a moderately worse progression-free survival (PFS) in PIK3CAm versus wild-type (WT) (24 m vs. 30 m; HR = 1.39, p = 0.26). A subanalysis was carried out based on exons 9 and 20, which showed a statistically poorer PFS in PIK3CAm exon 9 versus 20 population (9.7 m vs. 30.3 m; HR = 2.84; p = 0.024). Furthermore, detection of PIK3CAm in plasma was linked to a worse PFS vs PIK3CAm detection just in tissue (12.4 vs. 29.3; HR = 2.4; p = 0.08). CONCLUSIONS: Our findings suggest the PIK3CA evaluation in tissue as the diagnostic method of choice, however, additional investigations are required to improve the role of liquid biopsy in the PIK3CA assessment. PIK3CAm show worse outcomes in advanced luminal BC, especially in exon 9 mutation carriers, despite visceral involvement, prior exposure to endocrine therapy or detection of PIK3CAm in plasma, with an unclear prognosis in early-stage disease. Nonetheless, this should be validated in a prospective cohort study.

[Biological characteristics of triple negative breast cancer with low expression of HER2].

Objective: To investigate the biological characteristics of triple negative breast cancer (TNBC) with low expression of HER2 (HER2-low). Methods: A total of 93 TNBC cases in Shanxi Cancer Hospital from 2017 to 2019 were collected and divided into HER2-negative and HER2-low groups according to HER2 expression status. The clinicopathological features and prognostic differences between the two groups were retrospectively analyzed and compared, and genetic detection of tumor tissues was performed to clarify somatic mutation status and differences between the two groups. Results: Ninety-three patients aged 26 to 86 years were enrolled, including 60 patients in the HER2-negative group and 33 patients in the HER2-low group. The distribution of HER2-low in luminal androgen receptor (LAR) subtype (14/23, 60.87%) and non-LAR subtype (19/70, 27.14%) was significantly different (P=0.005). There were no significant differences in age, pT stage, histological grade, infiltration mode, lymph node metastasis and survival analysis. The expression of HER2-low in the tumor was heterogeneous, including different proportions of weak, weak to moderate intensity, and incomplete to intact membrane staining. With the change of the proportion of HER2-positive cells, the different distribution of those cells in the total tumor cells was noted, including cluster, mosaic and scattered patterns. The concentration and quality of DNA extracted from 71 of the 93 samples met the requirements for making libraries, including 43 in the HER2-negative group and 28 in the HER2-low group. Genetic mutations were mainly missense mutations, single nucleotide mutations, and point mutations in which base C was replaced by base T. There was no significant difference in genes with mutation frequency>3 times between the two groups. CTNNB1 and FGFR3 genes were only mutated in HER2-low group; while ALK, CYP2D6 and FAT1 genes were only mutated in HER2-negative group. HER2-low group included 18 HER2 1+ cases and 10 HER2 2+ cases. Genes with mutation frequency>3 times between the two groups included PIK3CA, TP53, SLX4, ATM and BRCA1. The mutation frequency of PIK3CA in HER2 2+ was significantly higher than that in HER2 1+ group (P<0.05), and SLX4 gene was only mutated in HER2 1+ group. Conclusions: There are some differences of histological morphology and genetic variation between HER2-negative group and HER2-low group, and also differences in genetic variation between HER2 1+ and HER2 2+ in HER2-low group, which are helpful for more accurate stratification of TNBC and useful for finding the therapeutic target and precise treatment of HER2-low TNBC.

Molecular Analysis of Renal/Adrenal Angiosarcomas Reveals High Frequency of Recurrent Genetic Alterations.

Angiosarcomas of the kidney and adrenal gland are rare, highly aggressive vascular neoplasms. Their genomic profile has not been systematically studied to date. We report the clinicopathologic and molecular features of six angiosarcomas centered in the kidney/adrenal gland. All patients were male adults, ranging from 58 to 77 years of age. Tumor sizes ranged from 2.5 to 22.5 cm. Half of the cases demonstrated hot spot mutations in the KDR gene, while one-third demonstrated mutations in the PIK3CA gene; both of these gene alterations being previously described, preferentially in breast angiosarcomas. In addition, two cases each demonstrated BRIP1 gene amplification, CTNNB1 and ETV6 mutations, which have not been previously reported in angiosarcoma. Notably, molecular studies were critical in establishing the correct diagnoses in three cases: one was an epithelioid angiosarcoma originally misdiagnosed as metastatic adenocarcinoma to the adrenal gland, the second was a vasoformative angiosarcoma that mimicked hemangioma, and the third was a collision tumor between a high-grade angiosarcoma and a chromophobe renal cell carcinoma which was originally diagnosed as a sarcomatoid renal cell carcinoma. In summary, angiosarcomas of the kidney and adrenal gland have a high frequency of recurrent genetic alterations, some of them being shared with other angiosarcoma subtypes, while other appear to be novel. In particular, activating hot spot KDR and PIK3CA mutations represent potential therapeutic targets for these highly aggressive cancers.

Molecular genetic analysis of colorectal carcinoma with an aggressive extraintestinal immunohistochemical phenotype.

Colorectal cancer (CRC) is a leading global cause of illness and death. There is a need for identification of better prognostic markers beyond traditional clinical variables like grade and stage. Previous research revealed that abnormal expression of cytokeratin 7 (CK7) and loss of the intestinal-specific Special AT-rich sequence-binding protein 2 (SATB2) are linked to poor CRC prognosis. This study aimed to explore these markers' prognostic significance alongside two extraintestinal mucins (MUC5AC, MUC6), claudin 18, and MUC4 in 285 CRC cases using immunohistochemistry on tissue microarrays (TMAs). CK7 expression and SATB2-loss were associated with MUC5AC, MUC6, and claudin 18 positivity. These findings suggest a distinct "non-intestinal" immunohistochemical profile in CRC, often right-sided, SATB2-low, with atypical expression of CK7 and non-colorectal mucins (MUC5AC, MUC6). Strong MUC4 expression negatively impacted cancer-specific survival (hazard ratio = 2.7, p = 0.044). Genetic analysis via next-generation sequencing (NGS) in CK7 + CRCs and those with high MUC4 expression revealed prevalent mutations in TP53, APC, BRAF, KRAS, PIK3CA, FBXW7, and SMAD4, consistent with known CRC mutation patterns. NGS also identified druggable variants in BRAF, PIK3CA, and KRAS. CK7 + tumors showed intriguingly common (31.6%) BRAF V600E mutations corelating with poor prognosis, compared to the frequency described in the literature and databases. Further research on larger cohorts with a non-colorectal immunophenotype and high MUC4 expression is needed.