Organic cation transporter 2 and tumor budding as independent prognostic factors in metastatic colorectal cancer patients treated with oxaliplatin-based chemotherapy

Oxaliplatin is currently approved for patients with metastatic colorectal cancer (mCRC). Its uptake and consequent cytotoxicity is determined by the levels of organic cation transporter 2 (OCT2). In addition, tumor budding (TB) is associated with high malignant potential. However, the impact of the levels of OCT2 and TB on clinicopathological findings and the prognosis of mCRC patients treated with oxaliplatin-based chemotherapy remains unclear. Here, 80 mCRC patients were retrospectively assessed. Immunohistochemistry was performed to determine the levels of OCT2 and TB. High levels of OCT2 (47/80, 59%) were detected at the invasion front and were associated with depth of invasion (P=0.03), whereas high levels of TB (40/80, 50%) were associated with extensive lymphatic invasion (P=0.03). In univariate analysis, high OCT2 levels were significantly correlated with longer progression-free survival (PFS) (P=0.02) whereas high TB levels were associated with shorter PFS (P=0.01). In combined analysis, patients with 2 favorable factors (high OCT2/low TB) had longer PFS than those with 1 (P=0.03) or 0 (P