Fig. 1

Serum carbonic anhydrase IX (CAIX) levels during neoadjuvant treatment of patients with locally advanced rectal cancer. Using a commercially available immunoassay, CAIX was measured in serum sampled from the study patients at baseline (n = 66), following four weeks of neoadjuvant chemotherapy (post-NACT; n = 66), at completion of a 5-week course of chemoradiotherapy (post-CRT; n = 54) and at evaluation of the neoadjuvant therapy four weeks later (n = 50). CAIX values are depicted by boxes (25th, 50th and 75th percentiles), bars (10th and 90th percentiles) and circles (outlier values). Distribution of CAIX values during the neoadjuvant course was different from baseline (* p < 0.05, ** p < 0.001; calculated by Mann-Whitney U-test)