The same question applies, also, for breast cancer, where breast-cancer cell lines, when assessed by the SA-b-gal marker, are negative for the senescence phenotype but can stain positive by either gene manipulations, such as HER2 overexpression and PKCη knock-down, or cancer-therapy-relevant treatments (anti-HER2 or Doxorubicin) [48,49,50,51]. The gene discussed is ERBB2; the disease is breast cancer.