Análisis de la coexpresión de HER2/GRB7 y su asociación con variables clinicopatológicas en un grupo de mujeres colombianas con diagnóstico de cáncer de mama invasivo / Analysis of HER2/GRB7 co-expression and its association with clinicopathological variables in a group of Colombian women diagnosed with invasive breast cancer

Objetivo. Analizar las diferencias en la presentación de variables clínico-patológicas, de acuerdo con la expresión proteica de GRB7, en tumores HER2 positivos en mujeres colombianas con cáncer de mama invasivo, diagnosticado entre los años 2013 y 2015 en el Instituto Nacional de Cancerología E.S.E (INC). Métodos. Se incluyeron 158 pacientes con diagnóstico confirmado de cáncer de mama ductal invasivo. Se evaluó la expresión de los receptores hormonales (receptor de estrógeno (RE) y de progesterona (RP)), HER2, Ki67 y GRB7, mediante inmunohistoquímica (IHQ), y a partir de estos, se clasificaron los tumores en subtipos intrínsecos. Los análisis estadísticos incluyeron las pruebas de Chi-cuadrado/test exacto de Fisher para las variables categóricas, y la prueba U Mann Whitney/ Kruskal Wallis para las variables cuantitativas. Se evaluó la supervivencia global (SG) y libre de enfermedad (SLR) según la coexpresión de HER2/GRB7 usando el método de Kaplan-Meier y el test de log-rank. Resultados. La expresión de GRB7 se observó exclusivamente en tumores HER2-positivos (luminal B/HER2+ y HER2-enriquecidos: p<0,001). Los casos HER2+/GRB7+ mostraron una mayor expresión de Ki67 (40% vs. 27,5%, p=0,029), pero una tendencia a presentar un menor tamaño tumoral (30 mm vs. 51 mm, p=0,097), comparado con los tumores HER2+/GRB7-. No obstante, no se observaron diferencias en la supervivencia según la coexpresión de HER2/GRB7 (SG: p=0,6; SLR: p=0,07). Conclusiones. En nuestra muestra de estudio, la expresión de GRB7 en tumores HER2+ no se asoció con características clínico-patológicas de pronóstico desfavorable.

Objective: To analyze differences in the presentation of clinicopathological variables according to GRB7 protein expression in HER2-positive tumors in Colombian patients with invasive ductal breast carcinomas diagnosed between 2013 and 2015 at the Instituto Nacional de Cancerología (Bogotá, Colombia).Methods: A total of 158 breast cancer patients were included with a confirmed diagnosis of invasive ductal carcinoma. A single pathologist evaluated the protein expression of hormone receptors (estrogen (ER) and progesterone receptor (PR)), HER2, Ki67, and GRB7 by immunohistochemistry (IHC). The chi-square and Fisher's exact tests were used to assess differences between categorical variables, as well as the Mann-Whitney/Kruskal-Wallis U test for numerical variables. Overall (OS) and disease-free (DFS) survival were evaluated according to HER2/GRB7 co-expression using the Kaplan-Meier method and log-rank test.Results:GRB7 expression was observed exclusively in HER2-positive tumors (luminal B/HER2+ and HER2-enriched: p<0.001). HER2+/GRB7+ cases showed higher Ki67 expression (40% vs. 27.5%, p=0.029) and a tendency to present a smaller tumor (30 mm vs. 51 mm, p=0.097) compared to HER2+/GRB7- tumors. However, no differences in OS or DFS were observed by HER2/GRB7 co-expression (OS: p=0.6; DFS: p=0.07).Conclusions:Our results in Colombian patients indicate that GRB7 expression in HER2-positive breast tumors is not associated with unfavorable clinicopathological features.

High prevalence of luminal B breast cancer intrinsic subtype in Colombian women.

Breast cancer is the most frequent malignancy in women worldwide. Distinct intrinsic subtypes of breast cancer have different prognoses, and their relative prevalence varies significantly among ethnic groups. Little is known about the prevalence of breast cancer intrinsic subtypes and their association with clinicopathological data and genetic ancestry in Latin Americans. Immunohistochemistry surrogates from the 2013 St. Gallen International Expert Consensus were used to classify breast cancers in 301 patients from Colombia into intrinsic subtypes. We analyzed the distribution of subtypes by clinicopathological variables. Genetic ancestry was estimated from a panel of 80 ancestry informative markers. Luminal B breast cancer subtype was the most prevalent in our population (37.2%) followed by luminal A (26.3%), non-basal triple negative (NBTN) (11.6%), basal like (9%), human epidermal growth factor receptor 2 (HER2) enriched (8.6%) and unknown (7.3%). We found statistical significant differences in distribution between Colombian region (P = 0.007), age at diagnosis (P = 0.0139), grade (P < 0.001) and recurrence (P < 0.001) according to intrinsic subtype. Patients diagnosed with HER2-enriched, basal-like and NBTN breast cancer had the highest African ancestry. Future studies analyzing the molecular profiles of breast cancer in Colombian women will help us understand the molecular basis of this subtype distribution and compare the molecular characteristics of the different intrinsic subtypes in Colombian patients.

Regulation of epithelial-mesenchymal transition through epigenetic and post-translational modifications.

The epithelial to mesenchymal transition (EMT) is a biological process in which a non-motile epithelial cell changes to a mesenchymal phenotype with invasive capacities. This phenomenon has been well documented in multiple biological processes including embryogenesis, fibrosis, tumor progression and metastasis. The hallmark of EMT is the loss of epithelial surface markers, most notably E-cadherin, and the acquisition of mesenchymal markers including vimentin and N-cadherin. The downregulation of E-cadherin during EMT can be mediated by its transcriptional repression through the binding of EMT transcription factors (EMT-TFs) such as SNAIL, SLUG and TWIST to E-boxes present in the E-cadherin promoter. Additionally, EMT-TFs can also cooperate with several enzymes to repress the expression of E-cadherin and regulate EMT at the epigenetic and post- translational level. In this review, we will focus on epigenetic and post- translational modifications that are important in EMT. In addition, we will provide an overview of the various therapeutic approaches currently being investigated to undermine EMT and hence, the metastatic progression of cancer as well.