Prognostic value of broad-spectrum keratin clones AE1/AE3 and CAM5.2 in small cell lung cancer patients undergoing pulmonary resection.

INTRODUCTION: Small cell lung carcinoma (SCLC) is an aggressive pulmonary neoplasm of neuroendocrine origin. Keratins form a large group of intermediate filaments, which are major structural proteins in epithelial cells and carcinomas. SCLC shows a wide spectrum of keratin expression, from very strong to completely negative. A prognostic role of keratin expression in SCLC is unknown. MATERIAL AND METHODS: Tumor tissue microarray samples from a unique series of 82 SCLC patients who underwent pulmonary resection were stained with keratin specific antibodies AE1/AE3 and CAM5.2. The percentage o1f positively stained cells and their staining pattern (diffusely membranous, partially membranous and dot-like) were evaluated. The median expression value was used for the distinction between keratin-negative and -positive patients. Overall survival in respective groups was compared using the log-rank test. Multivariate Cox proportional hazards regression analysis was performed adjusting for age, gender, tumor site, tumor stage, and tumor histology. RESULTS: edian expression of AE1/AE3 and CAM5.2 was 80% and 90%, respectively. Five cases were completely negative for AE1/AE3 and three for Cam5.2. Median overall survival for patients with stronger and weaker AE1/AE3 staining was 24.7 and 13.8 months, respectively (p=0.019). There was no difference in survival in relation to the CAM5.2 expression (p=0.44). In multivariate analysis adjusted for CAM5.2, T and N stage, gender and age at diagnosis, stronger AE1/AE3 expression was an independent predictor of increased survival (HR 0.50; 95% CI, 0.27-0.94; p=0.031). CONCLUSION: High expression of AE1/AE3 is a favorable prognostic factor in surgically treated SCLC. The applicability of this finding to a typical patient population treated with non-surgical methods warrants further studies.

Keratin 7 expression in lymph node metastases but not in the primary tumour correlates with distant metastases and poor prognosis in colon carcinoma.

Colorectal carcinoma (CRC) is one of the leading causes of cancer-related deaths worldwide. Alterations in keratin expression, including keratin 7 (K7), are frequent findings in multiple cancers, and they constitute a prognostic factor. The aim of our study was to evaluate the prognostic significance of K7 in the primary tumour and lymph node metastases in two separate cohorts of patients: the first one with lymph node involvement (LN+, 129 cases) and the second one free of LN metastases (LN-, 85 cases). Keratin 7 expression in CRC was analysed on tissue microarrays with immunohistochemistry and evaluated using the h-score. In the LN+ group K7 positivity was identified in 7/129 (5.4%) of primary tumours (PT) and lymph node metastases (LNM); concordance between them was 94% ( 0.396). Keratin 7 was expressed in 8/85 cases (9.4%) in the LN- group. K7 expression in LNM of the LN+ cohort correlated with shorter overall survival (OS) (p = 0.047) and presence of distant metastases at diagnosis (p = 0.005). Expression of K7 in the primary tumour in both cohorts did not correlate with survival. We conclude that the status of K7 expression in metastatic lymph nodes from CRC is a poor prognostic factor.