ENTERIC ALPHA-1-ANTITRYPSIN LOSS AND COMPARISON WITH OKOKIT-II AND HEMOCCULT FOR THE DETECTION OF COLORECTAL-CANCER

Faecal samples from patients with symptomatic colorectal cancer (n = 1 9) and from control subjects (n = 54) were analysed for alpha-1-antitr ypsin (A1AT) and compared with Haemoccult and Okokit II. A1AT was also measured in paired samples of normal colonic mucosa and cancer tissue (n = 16) and in media from four human colorectal cell lines (COLO 320 DM, SW620, HT29, LS 174T). Faecal A1AT concentrations were greater th an controls (P < 0.0001) and detected 12 (63%) patients with cancer co mpared to 10 (53%) by Okokit II and 7 (37%) by Haemoccult (P > 0.05). A1AT concentrations from colonic mucosa (median, range: 0.46, 0.17-0.7 9 mg/g wet wt) were greater (P = 0.01) than cancer tissue (0.29, 0.13- 0.74 mg/g wt wt). Adjusting for albumin, A1AT concentrations from muco sa (12.0, 3.8-32.2 mg/g albumin) remained greater (P = 0.003) than for cancer tissue (5.9, 2.4-21.4 mg/g albumin). A1AT was not detected in any of the cell-line media. The most likely mechanisms for increased f aecal A1AT concentrations, apart from increased blood loss, are increa sed cell turnover or leakage from epithelial tight junctions. The use of faecal A1AT measurement for the detection of colorectal cancer dese rves further assessment.