Immunohistochemical Expression of Calretinin in Invasive Breast Carcinoma and its Correlation with Clinicopathological Parameters.

Background: Breast cancer (BC) is the most common cancer and foremost cause of death in women.

Objective: This study was conducted to study the calretinin expression in BC and its correlation with other clinicopathological parameters such as tumor size, histological grade, lymph node status, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2/neu), Ki67 status and molecular subtypes in Indian setting.

Methods: Fifty cases of BC diagnosed between 2017 and 2019 were included in the study. A technique of manual tissue microarray was employed for the analysis of expression of IHC markers such as calretinin, ER, PR, Her2/neu, Ki67, CK5/6 and EGFR in all cases. Results were subjected to statistical analysis.

Results: Calretinin positivity was seen in 66% (33/50) cases of BC of which 45.45% (19/33) were triple negative BC (TNBC) and 21.21% (7/33) were of basal like BC (BLBC) molecular subtype. Calretinin expression was significantly associated with higher grade and negative ER and PR expression. Maximum cases expressing calretinin showed lymphovascular invasion (LVI), positive lymph node status, higher stage, Ki67 and HER2/neu positivity. 38% cases were TNBC. Calretinin was found positive in 78.95% of TNBC cases. Calretinin expression was seen in TNBC cases of higher grade and stage with positive lymph node status, presence of LVI and Ki67 positivity.14% cases were BLBC. Calretinin was found positive in 77.78% of BLBC cases. Calretinin expression was seen in BLBC cases of higher grade and stage with positive lymph node status, Ki67 positivity and presence of LVI.

Conclusions: Calretinin can be potentially used as a prognostic marker and could be included in routine IHC workup of BC cases which could aid in development of tailored therapy.