Expression of p27Kip1 and E-cadherin in HNSCC tumors

Malignant tumors are expected to show characteristic features in DNA damage and the corresponding protein expression. In principle, damage could be particularly severe if it inactivates tumor suppressor genes, the status of which could be useful as cancer markers. Objectives: This study aimed to investigate the correlations between histopathologically assessed malignancy and the expression status of the tumor suppressor genes E-cadherin and p27Kip1 in head-and-neck squamous cell carcinoma (HNSCC). Methods: The expression of E-cadherin and p27Kip1 has been immunohistochemically tested from HNSCC tumors from 57 patients, including 45 primary tumors and 12 unrelated lymph nodal tumors for comparison. Tumor samples were obtained from the archives of Indonesian hospitals, in accordance with acknowledged ethical requirements. To test for association and differences between grouped results, the nonparametric Mann-Whitney U testing was used, assuming p < 0.05 to imply significance. To test for correlations, Spearman correlation and linear regression were applied. Results: The results show a low but significant correlation of increasing tumor malignancy with decreasing expression of both E-cadherin and p27Kip1. The expression levels of E-cadherin and p27Kip1 in both primary and nodal tumors were strongly correlated ((r=0.9). Conclusion: In conclusion, there is large scatter and only modestly significant association between high level of tumor malignancy and low expression of E-cadherin or p27Kip1. Strong correlation in the expression levels of E-cadherin and p27Kip1 suggests practically full correspondence between the two tumor suppressors. Tight correlation also means that their predictive power will not improve when used in combination as cancer markers.