As the antiproliferative effect of the combination can depend on the different genetic background of the cells [21], we selected two human pancreatic cancer cell lines, BxPC-3 and Capan-1, both p53-mutated (point mutations A159V in Capan-1 and Y220C in BxPC-3) [22, 23] but differing in KRAS status (point mutation G12V in Capan-1 and wild type in BxPC-3) [22, 23] and EGFR protein expression levels (low in Capan-1 and high in BxPC-3) [24], and analyzed in detail the antiproliferative response to erlotinib and gemcitabine in both systems. The gene discussed is EGFR; the disease is familial pancreatic carcinoma.