PROLIFERATING CELL NUCLEAR ANTIGEN EXPRESSION CORRELATES WITH THE METASTATIC POTENTIAL OF SUBMUCOSAL INVASIVE COLORECTAL-CARCINOMA

To examine the malignant potential of submucosal invasive colorectal c arcinoma, the relationship between proliferating cell nuclear antigen (PCNA) expression and clinicopathologic risk factors for lymph node me tastasis was studied in 149 patients with submucosal invasive colorect al carcinoma. The depth of submucosal invasion was classified as scant y or massive. Histologic subclassification at the submucosal deepest i nvasive portion was done as follows: well differentiated (W), moderate ly well differentiated (Mw), moderately poorly differentiated (Mp) or poorly differentiated (For). Tumor growth was divided into polypoid gr owth and nonpolypoid growth. The PCNA expression (labeling index, LI) was examined at the submucosal deepest invasive portion. The PCNA-LI o f tumors showing lymph node metastasis (mean, 56.5 +/- 19.0%) was sign ificantly higher than that of tumors without lymph node metastasis (me an, 41.5 +/- 19.3%; p < 0.01). The PCNA-LI of Mp tumors (mean, 57.7 +/ - 16.5%) was significantly higher than that of W (mean, 38.5 +/- 19.0% ; p < 0.05) and Mw (mean, 43.7 +/- 19.1%; p < 0.05) tumors. The PCNA-L I of tumors without adenomatous features (mean, 47.9 +/- 20.5%) was si gnificantly higher than that of tumors with such features (mean, 37.1 +/- 17.1%; p < 0.05). The PCNA-LI was not correlated with other risk f actors for lymph node metastasis, such as lymphatic invasion, depth of submucosal invasion, macroscopic type, and growth pattern. These resu lts indicate that the PCNA-LI may be useful marker for predicting the potential metastases to lymph nodes in submucosal invasive colorectal carcinoma, while the proliferative activity of cancer cells correlates with the degree of the differentiation in the area of deepest invasio n.