COMPARISON OF PROLIFERATING CELL NUCLEAR ANTIGEN VERSUS THE MORE STANDARD MEASURES OF RECTAL MUCOSAL PROLIFERATION RATES IN SUBJECTS WITH AHISTORY OF COLORECTAL-CANCER AND NORMAL AGE-MATCHED CONTROLS

Measurement of proliferation rates by the more standard in vitro uptak e techniques of [H-3]thymidine and 5'-bromo-2'-deoxyuridine (BrdUrd) l abeling indices (LIs) were compared to proliferating cell nuclear anti gen (PCNA) in rectal mucosal biopsies from 16 subjects with resected c olorectal cancer and 14 normal age-matched controls, Correlation coeff icients for BrdUrd versus PCNA, [H-3]thymidine versus PCNA, and BrdUrd versus [H-3]thymidine were 0.691, 0.876, and 0.770, respectively, No significant differences (P > 0.05) were detected in total mean LIs bet ween the LI methods for the normal group, In contrast, total PCNA LIs were found to be significantly different in the resected cancer patien ts when compared to either BrdUrd (P = 0.005) or [H-3]thymidine (P < 0 .001). A significant difference (P = 0.010) in total PCNA LI but not i n total [H-3]thymidine or BrdUrd LIs was also observed between normal controls and resected colorectal cancer subjects, Compartmental analys is of the cancer group versus the normals showed a significant differe nce in compartments 1 and 3 for PCNA LIs only, The reproducibility of two PCNA LI counts was excellent (r = 0.9), In addition, the reliabili ty of mean LIs were >0.8 with the exception of [3H]thymidine in the no rmal group (0.7). These study results demonstrate that PCNA LIs in hum an rectal mucosal biopsies are correlated highly with other more commo nly used cellular proliferation measurements; however, PCNA LIs were f ound to be significantly higher than the other two methods in the rese cted colorectal cancer subjects.