Expression changes of BIK in breast cancer tissues of different histological subtypes.

OBJECTIVE: The objective of the study was to determine the expression levels of BIK in breast cancer (BC) tissues of different histological subtype and to delve into the participation of BIK in this type of cancer. MATERIALS AND METHODS: BIK and p-BIK (the phosphorylated form) protein expressions were tested by immunohistochemistry in BC tissue microarrays (Tumoral [n = 90] and adjacent [n = 40] tissues). RESULTS: The data revealed an overexpression of BIK in invasive ductal (Grades I, IIA, and IIB) and in lobular (Grades IIA and IIB) carcinomas compared to their respective adjacent tissues. By contrast, canalicular carcinoma (Grades I and IIB) and phyllodes tumors had very low expression levels of BIK. Only levels of p-BIK were shown to be increased in invasive ductal carcinoma (Grades I, IIA, and IIB). Meanwhile, quantitative polymerase chain reaction analysis showed lower BIK levels in MCF-10A and MCF-7 cells than in MDA-MB-231 and human mammary epithelial cells. In agreement with this, BIK protein was shown to be overexpressed in MDA-MB 231 relative to MCF-7 cells. CONCLUSIONS: Our results showed an association between BIK expression and the BC tumor subtype under study, which could be related to different BIK functions in the BC subtypes.

OBJETIVO: Determinar el grado de expresión de BIK en tejidos de cáncer de mama de diferente subtipo histológico para ahondar en la participación de BIK en este tipo de cancer. MÉTODO: Por medio de inmunohistoquímica se determinó la expresión de BIK y de su forma fosforilada (p-BIK) en microarreglos de tejidos (tumores [n = 90] y tejidos adyacentes [n = 40]) y líneas celulares. RESULTADOS: Los datos mostraron una sobreexpresión de BIK en los carcinomas de tipo ductal invasivo (grados I, IIA y IIB) y lobular (grados IIA y IIB) con respecto a sus tejidos adyacentes respectivos. En contraste, el carcinoma canalicular (grados I y IIB) y los tumores filoides mostraron una baja expresión de BIK en relación con sus tejidos adyacentes respectivos. El análisis de la qPCR mostró una menor expresión de BIK en las células MCF-10A y MCF-7 en comparación con las células MDA-MB-231 y HMEC. En concordancia con esto, la expresión proteica de BIK fue mayor en las células MDA-MB 231 que en las células MCF-7. CONCLUSIÓN: Nuestros resultados mostraron una asociación entre la expresión de BIK y el subtipo tumoral en estudio, lo cual sugiere una función diferencial de BIK en el cáncer de mama.

Usefulness and limitations of E-cadherin and ß-catenin in the classification of breast carcinomas in situ with mixed pattern.

BACKGROUND: The distinction between lobular neoplasia of the breast and ductal carcinoma in situ has important therapeutic implications. In some cases, it is very difficult to determine whether the morphology of the lesion is ductal or lobular. The aim of this study was to evaluate the value of E-cadherin and ß-catenin expression through the immunophenotypical characterization of carcinoma in situ with mixed pattern (CISM). METHODS: A total of 25 cases of CISM were analyzed considering cytology/mixed architecture (ductal and lobular), nuclear pleomorphism, loss of cell cohesion, and presence of comedonecrosis. The immunophenotype pattern was considered E-cadherin positive and ß-catenin positive, or negative. RESULTS: Nineteen (76%) cases presented a mixed cytology and / or architectural pattern, two (8%) presented nuclear pleomorphism, two (8%) presented mixed cytology and nuclear pleomorphism, and two (8%) presented comedonecrosis and nuclear pleomorphism. A complete positivity for E-cadherin and ß-catenin was observed in 11 cases (44%). In one case, the lesion was negative for both markers and showed nuclear pleomorphis. Thirteen lesions showed negative staining in areas of lobular cytology and positive staining in cells presenting the ductal pattern. CONCLUSIONS: The expression of E-cadherin and ß-catenin, combined with cytological and architectural analysis, may highlight different immunophenotypes and improve classification of CISM. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/ 1693384202970681