p27 cell-cycle inhibitor is inversely correlated with lymph node metastases in right-sided colon cancer

p27, a cyclin-dependent kinase inhibitor, suppresses proliferation of norma l and neoplastic cells. Expression of p27 is correlated with survival in co lon cancer. To some degree, right-sided colon cancers differ biologically a nd clinically from left-sided colon cancers. We analyzed 41 patients with r ight-sided colon cancers, including 18 cases with regional lymph node metas tases and 23 cases with negative lymph nodes. Immunostaining for p27 was pe rformed on histologic sections of primary cancers and scored. Correlation o f p27 protein expression with histologic parameters was performed by t-test and multivariate analysis. Decreased p27 protein expression was associated with large tumor size. As percentages of positively stained tumor cells de creased from 70 to 29%, the mean tumor size increased from 1.9 to 7.3 cm. p 27 protein expression significantly decreased in primary cancers with angio lymphatic invasion or with positive lymph nodes in comparison with those wi thout angiolymphatic invasion (26 +/- 6 vs. 44 +/- 5%, P < 0.03) or with ne gative lymph nodes (23 +/- 4 vs. 47 +/- 6%, P < 0.003). p27 expression was not statistically different in terms of depth of tumor invasion (T1/T2 vs. T3/T4), tumor type or tumor differentiation. Multivariate analysis revealed that low p27 expression in primary cancers was correlated with lymph node metastases (P = 0.01). However, it did not correlate with any other histolo gic parameters. In summary, decreased p27 expression was associated with an increased likelihood of lymph node metastases in colon cancers, independen t of depth of tumor invasion. This implies that p27 is a potentially import ant predictor for tumor metastasis and patient's prognosis in right-sided c olon cancers. J. Clin. Lab. Anal. 13:291-295, 1999. (C) 1999 Wiley-Liss. In c.