[Abnormal expression of Thy-1 as a novel tumor marker in lung cancer and its prognostic significance].

Objective: The purpose of this study was to investigate the expression of Thy-1 immunohistochemically in different lung tumors and its prognostic significance in non-small cell lung cancer (NSCLC) cases. We also evaluate relationship between Thy-1 and p53 expression status so as to find any clue about the mechanism.

Methods: In this study, we used anti-Thy-1/CD90 antibody to detect the expression pattern of Thy-1 in different lung tumor sections, which were embedded in paraffin blocks. The expressions of Thy-1 in 175 lung tissue cases, including different pathological types, were analyzed as tissue array form. We also detect expression status in 91 NSCLC among these cases and analyze the relationship between Thy-1 and p53. The relationship between Thy-1 expression and patients' survival was studied.

Results: We first found that anti-Thy-1 antibody can strongly stain a nuclear molecule in different type of lung cancer cells. Among lung cancer cases, 89 (56.7%) cases showed strong nuclear staining for Thy-1 specially. In univariate and multivariate analysis for 91 NSCLC patients we found TNM staging, lymph node status and Thy-1 overexpression in nuclei were independent factors to affect the prognosis of NSCLC patients. In lymph node non metastasis subgroup cases, Thy-1 negative patients had significant longer survival than Thy-1 positive cases (mean survival: 46.42 mons vs 38.56 mons, P = 0.0207). There was a significant association between Thy-1 and p53 expression (P < 0.0001).

Conclusion: There is a significant overexpressed Thy-1 located in lung cancer cell nucleus as compared to the normal tissue or benign tumor cells of lung, and it is one of the factors effected on the prognosis of NSCLC patients. This finding suggests that Thy-1 maybe a novel latent malignant marker in the lung cancer pathology. The association between Thy-1 and p53 expression in nucleus suggests that p53 protein and Thy-1 may have some interaction.