PGR and breast carcinoma: In contrast, luminal-like breast cancer cells (MCF7, T47D, BT474) showed a fourfold increase in expression of basal cytokeratins CK5 (Student’s t-test, p = 0.03) and CK14 (Student’s t-test, p = 0.02), and a significant reduction in PR expression after co-culture with NPCs (Student’s t-test, p = 0.04).