A, B: Xenograft tumors were generated by injecting 1 × 106 HT1376-EV or HT1376 ARRB2-OE cells subcutaneously into nude mice. Xenograft tumor growth, and response to Gemcitabine treatment was monitored weekly. Gem (25 mg/kg bodyweight) was administered intraperitoneally, twice per week. C, D, E: Analysis of CD44s, CD44v, ARRB2, and cytokeratin mRNA levels in HT1376 subcutaneous tumor xenografts by qPCR. Norm. levels: target mRNA levels normalized to β-Actin mRNA.