Perspectives on emerging technologies, personalised medicine, and clinical research for cancer control in Latin America and the Caribbean.

Challenges of health systems in Latin America and the Caribbean include accessibility, inequity, segmentation, and poverty. These challenges are similar in different countries of the region and transcend national borders. The increasing digital transformation of health care holds promise of more precise interventions, improved health outcomes, increased efficiency, and ultimately reduced health-care costs. In Latin America and the Caribbean, the adoption of digital health tools is in early stages and the quality of cancer registries, electronic health records, and structured databases are problematic. Cancer research and innovation in the region are limited due to inadequate academic resources and translational research is almost fully dependent on public funding. Regulatory complexity and extended timelines jeopardise the potential improvement in participation in international studies. Emerging technologies, artificial intelligence, big data, and cancer research represent an opportunity to address the health-care challenges in Latin America and the Caribbean collectively, by optimising national capacities, sharing and comparing best practices, and transferring scientific and technical capabilities.

Molecular Epidemiology of ALK Rearrangements in Advanced Lung Adenocarcinoma in Latin America.

OBJECTIVE: Latin American countries are heterogeneous in terms of lung cancer incidence and exposure to potential carcinogens. We evaluated the frequency and clinical characteristics of ALK rearrangements (ALKr) in Latin America. METHODS: A total of 5,130 lung cancer patients from 10 Latin American countries were screened for inclusion. ALKr detection was performed by fluorescence in situ hybridization (FISH), immunohistochemistry (IHC), and real-time reverse transcriptase-polymerase chain reaction (RT-PCR) to assess method variability. Demographic and clinicopathologic characteristics were analyzed. RESULTS: Among the 5,130 patients screened, 8.4% (n = 433) had nonevaluable FISH tests. Evaluable FISH analyses revealed positive ALKr in 6.8% (320/4,697) of the study population, which included patients from 9 countries. ALKr distribution for each country was: Mexico 7.6% (79/1,034), Colombia 4.1% (10/242), Argentina 6.0% (153/2,534), Costa Rica 9.5% (13/137), Panama 4.4% (5/114), Uruguay 5.4% (2/37), Chile 8.6% (16/185), Venezuela 8.9% (13/146), and Peru 10.8% (29/268). RT-PCR showed high positive (83.6%) and negative (99.7%) predictive values when compared to the gold standard FISH. In contrast, IHC only showed a high negative predictive value (94.6%). CONCLUSIONS: Although there is a clear country and continental variability in terms of ALKr frequency, this difference is not significant and the overall incidence of ALKr in Latin America does not differ from the rest of the world.

Distribution of molecular subtypes of advanced lung adenocarcinoma and clinical outcomes in a center of Argentina.

The prevalence of relevant oncogenic drivers in lung adenocarcinoma varies in our region and data on clinical outcomes is scarce. The objective of the study was to describe the prevalence of KRAS, BRAF and EGFR mutations and ALK translocations in patients with advanced lung adenocarcinoma, and to depict the clinical outcome according to treatment strategies. Patients with adequate tumor biopsy sampling were included. KRAS, BRAF and EGFR mutations were studied by Sanger sequencing. ALK translocations were studied by fluorescent in situ hybridization (FISH) and immunohistochemistry (IH) with antibodies against ALK with clones D5F3 and 5A4. Informed consent was signed by 118 patients and 84 (72%) with complete molecular analysis were included. KRAS mutations were detected in 16 samples (19%), EGFR in 11 (13%), 9 of them conferring sensitivity to EGFR inhibitors, and BRAF mutations in 1 (1%). ALK translocations were detected in 3 samples (4%). Median follow-up was 42.4 [interquartile range (IQR): 27.0-64.2] months. Globally, median overall survival was 10.3 [IQR: 5.6-20.2] months. Median survival was 10.8 [IQR: 6.0-20.3] months in the group of patients without detectable molecular alteration, 9.6 [IQR: 3.7-16.1] months in KRAS mutant population (HR: 1.08; p = 0.82) and 32.5 [IQR: 19.6-38.4] months in patients with ALK translocations or sensitizing EGFR mutated tumors treated with tyrosine kinase inhibitors (HR: 0.27; p = 0.03). In conclusion, the prevalence of molecular alterations and outcomes in our population is similar to that reported in other studies in Western countries.

Molecular pathology of acute kidney injury in a choline-deficient model and fish oil protective effect.

PURPOSE: The aim of this work was to investigate the potential protective effects of fish oil on the basis of kidney transcriptomic data on a nutritional experimental model. METHODS: Male weanling Wistar rats were divided into four groups and fed choline-deficient (CD) and choline-supplemented (CS) diets with vegetable oil (VO) and menhaden oil (MO): CSVO, CDVO, CSMO and CDMO. Animals were killed after receiving the diets for 6 days. Total RNA was purified from the right kidney and hybridized to Affymetrix GeneChip Rat Gene 1.0 ST Array. Differentially expressed genes were analyzed. RESULTS: All CSVO, CSMO and CDMO rats showed no renal alterations, while all CDVO rats showed renal cortical necrosis. A thorough analysis of the differential expression between groups CSMO and CDMO was carried out. There were no differential genes for p < 0.01. The analysis of the differential expression between groups CSVO and CSMO revealed 32 genes, 11 were over-expressed and 21 were under-expressed in CSMO rats. CONCLUSIONS: This work was part of a large set of experiments and was used in a hypothesis-generating manner. The comprehensive analysis of genetic expression allowed confirming that menhaden oil has a protective effect on this nutritional experimental model and identifying 32 genes that could be responsible for that protection, including Gstp1. These results reveal that gene changes could play a role in renal injury.

Prognosis recovery score of apical surgery Guided Bone Regeneration using cone beam computed tomography and digital bioinformatics.

Objective: Guided Bone Regeneration (GBR) is a dental surgical procedure that uses barrier membranes to prevent soft tissue invasion and conduct new bone growth. This study aimed to define a Prognosis Recovery score (PR score) to objectively classify post-surgery responders from non-responder patients who underwent GBR using Cone Beam Computed Tomography (CBCT). Methods: This prospective-observational-longitudinal-cohort study recruited 250 individuals who were assigned to: Conventional-Apical-Surgery (CAS, n = 39), Apical-Surgery using human fascia lata Membrane placement (ASM, n = 42), and Apical-Surgery using human fascia lata Membrane placement and lyophilized allograft Bone powder (ASMB, n = 39); and Apical-Surgery using collagen membrane Porcine origin and Bovine Bone-matrix (ASPBB, n = 130), an independent external validation cohort. Surgery was performed, and evolution was monitored by CBCTs at 0, 6-, 12-, 18-, and 24 months post-surgery. Results: Normalized lesion volumes were calculated, and non-linear time evolution morphology curves were characterized. The three-time evolution bone growth patterns were: a linear tendency (PR0), "S'' shaped log-logistic (PR1), and "C" cellular growth (PR2). The treatment success rates were PR2-46 %, PR2-88 %, and PR2-95 %/PR1-5% for CAS, ASM, and ASMB groups. The xenograft ASPBB counterpart achieved PR2-92 % and PR1-8%. The score PR had a sensitivity, specificity, and accuracy of 100 %. Conclusions: Patients' treatment success can be quantitatively, objectively, and precisely predicted with the Prognosis Recovery score (using only two CBCTs), according to their biological response to allograft or xenograft materials (time-evolution bone growth curves), reducing cost and radiation exposure. Clinical significance: Through digital imaging and bioinformatic analysis of bone regeneration observed in CBCTs, we defined a Prognosis Recovery (PR) score using only two CBCT volume assessments (0 and 6 months). The PR score allowed us to define three time-evolution curves depending on the biomaterials used and to classify patients in a quantitative, objective, and accurate way.

[Clinical-pathological features and gene profile in colorectal cancer]. / Caracteres clínico-patológicos y perfil genético en el carcinoma colorrectal.

Colorectal cancer is the third most frequent cancer in men and the second most frequent in women, with a worldwide incidence of approximately 1.2 million new cases per year. Our primary objective was to study the relationship between clinical and histological features of individuals with colorectal cancer and the mutational status of codons 12 and 13 of the KRAS gene (7 validated mutations), in order to find a histopathological marker to mutated tumors. The secondary objective was to determine how many patients had additional mutations in codons 15 and 61 of the KRAS gene, and codon 600 of the BRAF gene, which could modify the tumor phenotype. Sixty individuals with colorectal cancer (30 wild-type subjects and 30 with validated mutations in codons 12 and 13 of the KRAS gene) were selected. Exons 2 and 3 of the KRAS gene, and exon 15 of the BRAF gene were amplified and sequenced. The data collected were reviewed by a descriptive, univariate and/or multivariate analysis, as appropriate. In conclusion, no relation was found between clinical and histological features of individuals with colorectal cancer and their mutational status for codons 12 and 13 of the KRAS gene. This suggests that those easily available data do not allow predicting the response to anti-EGFR therapy. In patients with advanced colorectal adenocarcinomas and KRAS wild-type status, further study of codon 600 of the BRAF gene could be required.

Circulating tumor cells in cancer-risk populations as a cancer interception tool.

Cancer interception (CI) is a new approach to cancer prevention and treatment in a cancer-risk population that aims to detect and treat pre-tumoral stages. It has several potential advantages over traditional cancer diagnosis and monitoring methods because it is non-invasive, making it less painful and risky than conventional biopsy procedures. The circulating tumor cells (CTCs), liquid biopsy family members, are essential for the CI approach; then, the liquid biopsy (LB) is used as a CI tool. LB can be performed frequently because of its easy sampling and early pathological stages, which allow repeated non-invasive monitoring of cancer progression and response to treatment. CTCs have been found in the bloodstream of several types of cancer patients, including in early-stage cancer and premalignant lesions, suggesting a tumor development role in cancer's early stages. This chapter will present foundational scientific studies addressing CI and the clinical impact of CTC screening in a population at risk for cancer.

Clinical implementation of a cervical cancer screening program via co-testing at a university hospital.

The Human Papillomavirus (HPV) test is a crucial technology for cervical cancer prevention because it enables programs to identify women with high-risk HPV infection who are at risk of developing cervical cancer. Current U.S. Preventive Services Task Force recommendations include cervical cancer screening every three years with cervical cytology alone or every five years with either high-risk HPV testing alone or high-risk HPV testing combined with cytology (co-testing). In Argentina, 7,548 new cervical cancer cases are diagnosed each year with 3,932 deaths attributed to this cause. Our study aims to show the clinical implementation of a cervical cancer screening program by concurrent HPV testing and cervical cytology (co-testing); and to evaluate the possible cervical cancer screening scenarios for Latin America, focusing on their performance and average cost. A cervical cancer screening five year program via co-testing algorithm (Hybrid-2-Capture/cytology) was performed on women aged 30-65 years old at a university hospital. Statistical analysis included a multinomial logistic regression, and two cancer screening classification alternatives were tested (cytology-reflex and HPV-reflex). A total of 2,273 women were included, 91.11% of the participants were double-negative, 2.55% double-positive, 5.90% positive-Hybrid-2-Capture-/negative-cytology, and 0.44% negative-Hybrid-2-Capture/positive-cytology. A thorough follow-up was performed in the positive-Hybrid-2-Capture group. Despite our efforts, 21 (10.93%) were lost, mainly because of changes on their health insurance coverage which excluded them from our screening algorithm. Of the 171 women with positive-Hybrid-2-Capture results and follow-up, 68 (39.77%) cleared the virus infection, 64 (37.43%) showed viral persistence, and 39 (22.81%) were adequately treated after detection via colposcopy/biopsy of histological HSIL (High-Grade Squamous Intraepithelial Lesion). The prevalence of high-risk HPV in this population was 192 women (8.45%), with HSIL histology detection rates of 17 per 1,000 screened women. A multinomial logistic regression analysis was performed over the women with positive-Hybrid-2-Capture considering the follow up (clearance, persistence and HSIL) as dependent variable, and the cytology test results (positive- or negative-cytology and Atypical Squamous Cells of Undetermined Significance, ASC-US) as independent variable. The model supported a direct association between cytology test results and follow up: negative-cytology/clearance, ASC-US/persistence, and positive-cytology/HSIL with the following probabilities of occurrence for these pairs 0.5, 0.647 and 0.647, respectively. Cytology could be considered a prognostic-factor in women with a positive-Hybrid-2-Capture. These findings suggest that the introduction of co-testing could diminish the burden of cervical cancer in low-and middle-income-countries, acting as a tool against inequity in healthcare.

Diagnosis of an adenocarcinoma of Müllerian origin made as a result of its metastasis in the mouth floor.

Metastases derived from primary tumours distant to the oral and maxillofacial region account for only 1% of all malignancies at that location, usually with a poor prognosis. In women, the primary tumours that most frequently metastasise to the oral cavity are breast adenocarcinomas affecting the jawbones and soft tissues (41% and 24%, respectively), followed by adrenal glands and female genital organs to the jawbones (8%), and female genital organs to the soft tissues (15%). Metastatic tumours of the mouth are a challenging diagnosis because of their exceptional occurrence. We report on the case of an 83-year-old woman who consulted for a bleeding ulcerated tumour on the floor of the mouth. A biopsy-confirmed metastasis of an adenocarcinoma of Müllerian origin. The oral lesion was the first sign of undetected cancer. The patient agreed to surgical resection and was further referred to palliative care for her symptoms.

Small Cell Lung Cancer: State of the Art of the Molecular and Genetic Landscape and Novel Perspective.

Small cell lung cancer (SCLC) is a highly proliferative lung cancer that is not amenable to surgery in most cases due to the high metastatic potential. Precision medicine has not yet improved patients' survival due to the lack of actionable mutations. Intra- and intertumoral heterogeneity allow the neoplasms to adapt to various microenvironments and treatments. Further studying this heterogeneous cancer might yield the discovery of actionable mutations. First-line SCLC treatment has added immunotherapy to its armamentarium. There has been renewed interest in SCLC, and numerous clinical trials are underway with novel therapeutic approaches. Understanding the molecular and genetic landscape of this heterogeneous and lethal disease will pave the way for novel drug development.

Next generation sequencing for liquid biopsy based testing in non-small cell lung cancer in 2021.

Lung cancer is the leading cause of cancer death worldwide, with non-small cell lung cancer (NSCLC) representing its most commonly diagnosed sub-type. Despite the significant improvements in lung cancer biomarkers knowledge, accompanied by substantial technological advances in molecular tumor profiling, a considerable fraction (up to 30 %) of advanced NSCLC patient presents with major testing challenges or tissue unavailability for molecular analysis. In this context, liquid biopsy is on the rise, currently gaining considerable interest within the molecular pathology and oncology community. Molecular profiling of liquid biopsy specimens using next generation molecular biology methodologies is a rapidly evolving field with promising applications not exclusively limited to advanced stages but also more recently expanding to early stages cancer patients. Here, we offer an overview of some of the most consolidated and emerging applications of next generation sequencing technologies for liquid biopsy testing in NSCLC.

Liquid biopsy from research to clinical practice: focus on non-small cell lung cancer.

INTRODUCTION: In the current era of personalized medicine, liquid biopsy has acquired a relevant importance in patient management of advanced stage non-small cell lung cancer (NSCLC). As a matter of fact, liquid biopsy may supplant the problem of inadequate tissue for molecular testing. The term 'liquid biopsy' refers to a number of different biological fluids, but is most clearly associated with plasma-related platforms. It must be taken into account that pre-analytical processing and the selection of the appropriate technology according to the clinical context may condition the results obtained. In addition, novel clinical applications beyond the evaluation of the molecular status of predictive biomarkers are currently under investigation. AREAS COVERED: This review summarizes the available evidence on pre-analytical issues and different clinical applications of liquid biopsies in NSCLC patients. EXPERT OPINION: Liquid biopsy should be considered not only as a valid alternative but as complementary to tissue-based molecular approaches. Careful attention should be paid to the optimization and standardization of all phases of liquid biopsy samples management in order to determine a significant improvement in either sensitivity or specificity, while significant reducing the number of 'false negative' or 'false positive' molecular results.

Circulating Tumor Cells Enumeration from the Portal Vein for Risk Stratification in Early Pancreatic Cancer Patients.

BACKGROUND: Effective biomarkers are needed to enable personalized medicine for pancreatic cancer patients. This study analyzes the prognostic value, in early pancreatic cancer, of single circulating tumor cell (CTC) and CTC clusters from the central venous catheter (CVC) and portal blood (PV). METHODS: In total, 7 mL of PV and CVC blood from 35 patients with early pancreatic cancer were analyzed. CTC were isolated using a positive immunomagnetic selection. The detection and identification of CTC were performed by immunocytochemistry (ICC) and were analyzed by Epi-fluorescence and confocal microscopy. RESULTS: CTC and the clusters were detected both in PV and CVC. In both samples, the CTC number per cluster was higher in patients with grade three or poorly differentiated tumors (G3) than in patients with well (G1) or moderately (G2) differentiated. Patients with fewer than 185 CTC in PV exhibited a longer OS than patients with more than 185 CTC (24.5 vs. 10.0 months; p = 0.018). Similarly, patients with fewer than 15 clusters in PV showed a longer OS than patients with more than 15 clusters (19 vs. 10 months; p = 0.004). These significant correlations were not observed in CVC analyses. CONCLUSIONS: CTC presence in PV could be an important prognostic factor to predict poor prognosis in early pancreatic cancer. In addition, the number of clustered-CTC correlate to a tumor negative differentiation degree and, therefore, could be used as a diagnostic biomarker for pancreatic cancer.

Variable number tandem repeats in the promoter region of prostacyclin synthase gene in choline deficient rats.

Weanling Sprague-Dawley rats were fed on a choline-deficient diet with hydrogenated vegetable oil and corn oil as lipids develop acute renal failure. Pathogenesis of the latter is controversial and an ischemic mechanism has been proposed. Arachidonic acid derivatives are involved in the regulation of vascular tonus. Vasospasm could be due to an increase in tromboxane A2-mediated vasoconstriction or to a decrease in prostacyclin-induced vasodilatation. Enzymes involved in the synthesis of both compounds are tromboxane A2- and prostacyclin-synthase respectively. The aim of this study was to identify the variable number tandem repeats (VNTR) in the promoter region of prostacyclin synthase gene and verify if there exists a relationship between the occurrence of VNTR in those choline-deficient rats which die because of acute renal failure and those which do not. We verified the presence of the VNTR in the prostacyclin synthase rat gene, but we did not find any difference in the molecular weight of the alleles between experimental and control rats. Renal reparation of the acute kidney injury due to choline deficiency in some rats is not related with differences in VNTR in the promoter region of the prostacyclin synthase gene.

Correlation between PD-L1 expression (clones 28-8 and SP263) and histopathology in lung adenocarcinoma.

Lung cancer is the leading cause of cancer-related death worldwide. Recent advances in the management of non-small cell carcinoma are focused on the discovery of targeted therapies and novel immunotherapy strategies for patients with advanced disease. Treatment with anti PD-(L)1 immune checkpoint inhibitors requires the development of predictive biomarkers to select those patients that can most benefit from these therapies. Several immunohistochemical biomarkers have been developed in different technological platforms. However, the most useful and accessible for the daily clinical practice need to be selected. The objective of this study was to compare PD-L1 expression by automated immunohistochemistry in lung adenocarcinoma (ADC) FFPE samples with clones 28-8 and SP263 performed with the BenchMark GX automated staining instrument. To further determine interobserver agreement between two pathologists, and to correlate the results with histologic and pathology variables. FFPE tissue from 40 samples obtained from patients with lung ADC were reviewed retrospectively. Among all studied specimens, 53% of samples presented <1% of positive tumor cells with the 28-8 clone and 50% had <1% of PD-L1 expression in tumor cells with the SP263 clone; PD-L1 expression between ≥1 and <5% was observed in 18% and 24%; ≥5 and <50% PD-L1 expression in 18% and 21%; and ≥50% PD-L1 expression in 11% and 5% of samples, respectively. Similar results between antibodies were observed in 84% of cases for each of the four PD-L1 cutoff groups (Pearson's score 0.90, p < 0.00001). The interobserver degree of agreement calculated with Kappa was 0.75 (95%CI: 0.57-0.93), z = 7.08; p < 0.001. Lepidic, acinar and mucinous patterns had predominantly <1% PD-L1 expression, and the solid pattern subtype had high levels of PD-L1 staining using both clones. PD-L1 expression in less than 1% of tumor cells was similar in stages I/II compared to III/IV. No significant differences were observed in PD-L1 staining and quantification pattern between IHC antibodies 28-8 and SP263.

[Mutational status of BRAF and histopathological characteristics in cutaneous malignant melanoma]. / Estado mutacional de BRAF y parámetros histopatológicos en melanoma maligno cutáneo.

Malignant melanoma (MM) is the more aggressive form of skin cancer with a mortality rate in Argentina 1997-2001 = 1.1/100 000 in men and 0.6 in women. BRAF proto-oncogene is focus of intense research; its mutation is one of the main tumor promoters and occurs in approximately 50% of MM. Several drugs with clinical activity on BRAF mutations have been approved. The aim of the study is to evaluate the mutational status of BRAF (exon 15) in cutaneous MM biopsies and its relationship with histopathological characteristics. We carried out an observational, retrospective study of samples fixed in formaldehyde and paraffin embedded; reviewing age, sex, diagnosis, histopathological data, tumor size and percentage, viability for molecular analysis and melanin presence. We evaluated BRAF mutations with PCR/Sanger sequencing. For statistics we used Student's t test, Chi square, Wilcoxon and Fisher's exact test. We were able to purify and sequence 76% (38/49) samples, 13/38 (34%) from women and 25/38 (66%) from men, the median age being 70 years. Most frequent location: thorax 14/35 (40%). Histological type: Superficial spreading 18/38 (47%). Clark's levels, 11/38 (29%): I-II and 27/38 (71%): III, IV and V. Breslow's median: 1.6 mm. Radial growth phase 11/38 (29%) and 27/38 (71%) vertical. Presented mutations 16/38 (42%). As reported by other authors, no association was found between the mutational state of exon 15 and clinical or histopathological parameters.

El melanoma maligno es la forma más agresiva de cáncer de piel, con una tasa de mortalidad en Argentina 1997-2001 = 1.1/100 000 en varones y 0.6 en mujeres. El proto-oncogén BRAF es foco de intensa investigación, su mutación es uno de los principales promotores tumorales y pueden presentarse en 50% de los melanomas. Se han aprobado varios fármacos con actividad clínica sobre las mutaciones BRAF. El objetivo del trabajo es evaluar el estado mutacional de BRAF (exón 15) en biopsias con melanoma maligno cutáneo y su relación con las características histopatológicas. Realizamos un estudio observacional, retrospectivo, de muestras fijadas en formol e incluidas en parafina. Revisamos edad, sexo, diagnóstico y datos histopatológicos, tamaño y porcentaje tumoral, viabilidad para análisis molecular y presencia de melanina. Evaluamos mutaciones de BRAF con PCR/secuenciación Sanger. Utilizamos test de Student, Chi cuadrado, Wilcoxon y prueba exacta de Fisher. De 49 casos se pudo purificar y secuenciar el 76% (38/49), 13/38 (34%) mujeres y 25/38 (66%) varones, edad mediana 70 años. Localización más frecuente: tórax con 14/35 (40%). Tipo histológico: extensivo superficial 18/38 (47%). Niveles de Clark, 11/38 (29%): I-II y 27/38 (71%): III, IV y V. Mediana del Breslow: 1.6 mm. Fase de crecimiento radial 11/38 (29%) y 27/38 (71%) vertical. Presentaron mutaciones 16/38 (42%). Como lo informado por otros autores, no se encontró asociación entre el estado mutacional del exón 15 y los parámetros clínicos o histopatológicos.

Clinical and Economic Value of p16INK4a for the Differential Diagnosis of Morphologic Cervical Intraepithelial Neoplasia 2.

The detection of high-grade intraepithelial lesions requires highly sensitive and specific methods that allow more accurate diagnoses. This contributes to a proper management of preneoplastic lesions, thus avoiding overtreatment. The purpose of this study was to analyze the value of immunostaining for p16 in the morphologic assessment of cervical intraepithelial neoplasia 2 lesions, to help differentiate between low-grade (p16-negative) and high-grade (p16-positive) squamous intraepithelial lesions. The direct medical cost of the treatment of cervical intraepithelial neoplasia 2 morphologic lesions was estimated. A retrospective observational cross-sectional study was carried out. This study analyzed 46 patients treated with excisional procedures because of cervical intraepithelial neoplasia 2 lesions, using loop electrosurgical excision procedures. Immunostaining for the biomarker was performed. For the estimation of overtreatment, percentages (%) and their 95% confidence interval were calculated. Of the 41 patients analyzed, 32 (78%) showed overexpression of p16 and 9 (22%) were negative (95% confidence interval, 11%-38%). Mean follow-up was 2.9 years, using cervical cytology testing (Pap) and colposcopy. High-risk human papillomavirus DNA tests were performed in 83% of patients. These retrospective results reveal the need for larger biopsy samples, which would allow a more accurate prediction of lesion risk. Considering the cost of p16 staining, and assuming the proper management of the low-grade lesion, an average of US$919 could be saved for each patient with a p16-negative result, which represents a global direct cost reduction of 10%.

[Flow cytometry for the study of mediastinal tumors with abundant lymphoid elements]. / La citometría de flujo en el estudio de tumores mediastinales ricos en elementos linfoides.

The anterior mediastinum is a common site of tumors with abundant lymphoid elements. Flow cytometry is a useful complementary technique to analyze this type of tumors, which provides qualitative and quantitative information. A differential diagnosis can be sometimes made between thymoma and precursor T-lymphoblastic lymphoma (T-LBL). Correct identification is of utmost importance for patient treatment. A total of 38 mediastinal tumors were analyzed, and samples were separated for flow cytometry. Flow cytometry data from thymomas and normal thymic tissue were compared with 42 cases of T-LBL from other anatomical locations. Among 38 mediastinal tumors, we found 6 benign lesions, 9 diffuse large B-cell lymphomas (DLBCL), 10 Hodgkin lymphomas (HL), 11 thymomas and 2 T-LL. Flow cytometry provided positive information in 24 cases, and defined lymphoid neoplastic cells immunophenotype or the typical lymphocytes accompanying thymomas. Flow cytometry helped differentiate 10 cases of HL and 4 benign lesions from other lymphomas (DLBCL, T-LBL, etc.). CD3, CD4 and CD8 expressions were most useful for the differential diagnosis of thymomas and T-LL. To conclude, flow cytometry is a valid complementary technique, which promptly provides information on mediastinal lesions, requiring small quantities of tissue for both early diagnosis and follow up of these diseases.

[Immunohistochemistry of p16INK4a in biopsies and cervicovaginal smears, and its correlation with HPV detected by PCR]. / Inmunohistoquímica de la proteina p16INK4a en biopsias y extendidos cervicovaginales y su relación con HPV por PCR.

Recent studies suggest that p16 overexpression determined by immunohistochemistry would be a specific marker for neoplastic and dysplastic squamous cells associated with high-risk HPV. The purpose of this study was to assess the correlation between cyto-histological findings, p16 expression and HPV subtype. A total of 99 biopsies were selected, 4 endocervical curettages and 95 uterine cervix biopsies, as well as 30 cervicovaginal smears from other 30 patients. The samples were divided according to the morphological diagnosis. Paraffin-embedded sections and cervicovaginal smears were immunostained using the CINtec p16INK4a Cytology Kit (DAKO). HPV was analyzed by PCR in 25 of the 99 biopsies with low-grade squamous intraepithelial lesion. Among those patients with neither HPV nor dysplasia, 1 of 35 (2.9%) biopsies and 1 of 11 (9%) smears were positive for p16. Sixteen of 25 (64%) biopsies and 6 of 10 (60%) smears of the low-grade lesion cases, and 38 of 39 (97.4%) biopsies and 8 of 9 (89%) smears of the high-grade lesion and squamous carcinoma were positive for p16. All cases of HPV-6/11 were negative or focally positive for p16. Most cases of HPV-18 or other subtypes were diffusely positive. Our results indicate that p16 expression is highly correlated with cyto-histological diagnosis, and is associated with diffuse staining and high-risk HPV. This technique provides greater objectivity in doubtful cases, and helps select patients at risk of disease progression at an acceptable cost when used in large populations.