Prognostic value of nucleolar organizer regions in colorectal neoplasia.

The aims of the study were, firstly, to determine the frequency of nucleolar organizer regions (NORs) in normal colonic mucosa, adenomas and carcinomas, secondly, to determine the relationship of NOR frequency to adenoma diameter, carcinoma stage, patient survival and tumour recurrence. NOR frequency was determined in invasive carcinoma and adjacent normal mucosa in resection specimens from 46 patients with colorectal carcinoma and in 15 colorectal adenomas obtained at colonoscopy. NOR frequency was correlated with conventional prognostic criteria: adenoma diameter and carcinoma stage, tumour recurrence and patient survival. NOR frequency was significantly (P = 0.02) greater in carcinoma (median = 3.64) and adenoma (median = 2.30) compared to non-neoplastic mucosa (median = 1.96). NOR frequency was not significantly related to adenoma diameter, carcinoma node status, patient survival or tumour recurrence. NOR frequency increases with progression through adenoma to carcinoma. The poor association with conventional prognostic factors suggests that NOR frequency is of no value in prediction of adenoma or carcinoma behaviour and therefore does not closely reflect factors determining malignant cell behaviour.