Role of Smooth Muscle Actin and Cytokeratin 5/6 as Markers of Basallike Classification among Sudanese Triple Negative Breast Carcinoma Patients

Abstract

This is hospital based descriptive retrospective case study conducted in isotope hospital in Khartoum state, during the period from   March 2019 to June 2019. The study aimed to detect the expression Cytokeratin 5/6 and Smooth Muscle Actin in Triple Negative breast carcinoma tumors using immunohistochemical method. Thirty 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 one section of 3 micron thickness was cut from the microarray block by rotary microtome and stained by immunohistochemical method (avidin biotin technique) for detection of cytokeratin 5/6 and another for detection of smooth muscle actin. Data collected from patient's files and 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 40 years. Basal-like breast carcinoma revealed by strong positive expression of cytokeratin 5/6 in 25 (83.3 %) samples, while only 6 (20 %) were positive expression of smooth muscle actin among TNBC. There was significant correlation between the positive expression of CK 5/6 and the lack of expression of SMA, we found that the lack of SMA among the positive CK 5,6 was 21/25 (84 %) which agreed with Gorski, J.J et al. (2010) who found that the lack of SMA in basal-like breast cancers could reflect the activation of mechanisms responsible for the development of squamous metaplasia that also deregulate control of CK expression. Conclusion: On the basis of this study we conclude that the expression of CK 5/6 is more than SMA among TNBC, and also there is correlation between the expression of CK 5/6 and the lack of expression of SMA among TNBC.