Certain characteristics of the CL: ER positivity (first described by Lippman and Horwitz)24, 25; PR heterogeneity, which is generally attributed to the coexistence of several sublines, each possessing different stages of differentiation as well as dependent on the cell cycle phase and population doubling time (PDT)26; in microarray profiling, the cl genome clusters with the BC luminal type A type; HER2 negativity; additional expression of androgen and glucocorticoid receptors.23, 27. The gene discussed is ERBB2; the disease is breast cancer.