CAST and breast cancer: Studies have shown that high calpain-2 expression is associated with adverse breast cancer-specific survival in basal-like and triple-negative phenotype breast cancers [6], high calpain-1 expression and adverse relapse free survival in HER2 positive breast cancer patients treated with adjuvant chemotherapy and trastuzumab and high calpastatin expression with the absence of lymphovascular invasion determined by immunohistochemistry [7, 8].