Although group 2 tumors were positive to both CK5/6 and CK20 in >50% of tumor cells, the expression of CK5/6 and CK20 was accentuated in basal and luminal cells, leaving out at least one cell layer of the basal and luminal portion, respectively, in all cases (Figure 1B). The gene discussed is KRT5; the disease is neoplasm.