The Immunohistochemical Expression of the Oestrogen Receptor (ER), HER-2/NEU and Cytokeratin 8/18 and 5/6 in Invasive Breast Carcinoma.

INTRODUCTION: Carcinoma is the most common malignancy of the breast and breast cancer is the most common non-skin malignancy in women. Ideally, prevention or very early detection of breast cancer reduce both morbidity and mortality of the disease. Effective use of tumour markers might permit the application of screening and treatment more efficiently. MATERIALS AND METHODS: Immunohistochemical study was done in 39 cases of invasive breast carcinoma for further sub-classification for predicting prognosis and therapeutic approach. The cases were evaluated for expression of cytokeratin Ck 8/18, ER & Her-2/neu and 28 cases were subjected to cytokeratin Ck 5/6 including especially the cases negative for all the three markers. RESULTS: ER was positive in seven cases with Her-2/neu being positive in eight cases and cytokeratin 8/18 positive in 33 cases. Cytokeratin 5/6 was positive in seven cases with four cases showing Ck 5/6 and Ck8/18 positivity, three cases showing positivity for Ck 5/6 only and three cases were negative for all the four markers. CONCLUSION: Thus classifying them to be luminal A, luminal B, combined, basal and null type respectively. Luminal A tmours show the best prognosis while luminal B tumours , combined , basal and null type are associated with less favouable outcome. Thus it is important to categorise them according to the cell of origin for prognosis and treatment.

Cytokeratin 5/6 expression in benign and malignant breast lesions.

BACKGROUND: Cytokeratin s (CK) are used for the fingerprinting of carcinomas in general. In breast tissue, the luminal epithelial cells express CK 8/18, CK 7 and CK 19, while basal/myoepithelial cells express CK 5/6, CK 14 and CK 17. MATERIAL AND METHODS: Immunohistochemical staining for cytokeratin 5/6 was applied on cell block sections of 23 cases of benign and 25 cases of malignant breast lesions using avidin biotin peroxidase technique. The distribution and intensity of staining was recorded and graded semiquantitatively. RESULT: All benign lesions showed positive immunoreaction, with the staining index varying from 6-9, except lactating adenoma. The malignant lesions comprised three cases of ductal carcinoma in situ (DCIS) and 22 cases of infiltrating ductal carcinoma, not otherwise specified, IDC (NOS). None of the DCIS cases showed a positive immunoreaction. Among the IDC (NOS) lesions, six cases of grade III breast carcinoma exhibited a positive immunohistochemical reaction, the staining index of which varied from 2-6. The staining reaction in the malignant lesions was only cytoplasmic and the intensity was significantly less than that of benign lesions. CONCLUSION: CK 5/6 expression breast carcinoma implies a 'basal like' molecular phenotype and is associated with poor prognosis. This antibody is also used as a component of panels to differentiate benign and malignant breast lesions.