ERBB2 and breast carcinoma: Cathepsin L is a cysteine protease,(13) which shows a positive correlation with HPSE in three breast carcinoma subtypes, luminal A/B, HER2-enriched, and triple-negative (y=0.58x-0.69, R2=0.48, p=6.17 x 10-65, n=460; basal subtype, y=0.4291x-0.005506, R2=0.4691, p=0.0034; HER2-enriched, y=0.3187x-0.1288, R2=0.3480, p=0.0437; Luminal, y=0.3936x+0.003278, R2 =0.4144, p<0.0001) (Figure 3C).