Immunohistochemical Detection of Cytokeratin 5/6 and Smooth Muscle Actin among Triple Negative Breast Carcinoma in Sudanese Patients

Abstract

This is a hospital based descriptive retrospective study conducted in Radiation and Isotopes Center-Khartoum (RICK) hospital, during the period from March to June 2019. The study aimed to detect the expression of cytokeratin 5/6 and smooth muscle actin in triple negative invasive ductal carcinoma tissues using immunohistochemical method. Thirty formalin fixed paraffin embedded blocks from patients samples previously diagnosed as invasive ductal breast carcinoma with triple negative phenotype were collected. A tissue microarray block made and section of 4 micron thickness was cut from the microarray block by rotary microtome and stained by immunohistochemical method for detection of cytokeratin 5/6 and the same done for detection of smooth muscle actin. Data collected from patient's files and obtained results were analyzed using SPSS computer program. All thirty samples were invasive ductal carcinoma with triple negative phenotype. The patients age range between 20 to 70 years with mean age of 45 years. Based on the expression of cytokeratin 5/6 which differentiate between the basal and non-basal phenotype among the triple negative breast carcinoma, the Basal-like phenotype indicated by positive expression of cytokeratin 5/6 was in 25/30 (83.3 %) and the Non-basal-like phenotype indicated by the negativity of cytokeratin 5/6 was in 5/30 (16.7%) , while only 6/30 (20%) showed positive expression of smooth muscle actin among Triple Negative breast Carcinoma (TNBC). The study concluded that the expression of CK 5/6 is high (83.3%) among TNBC and the expression of SMA is low (20%) among TNBC. Also the lack of the expression of SMA in positive CK 5/6 expressed tissues is high (84%) among TNBC.