CD44 EXPRESSION IN METASTATIC AND NONMETASTATIC NONSMALL CELL LUNG CANCERS

CD44 is an integral membrane glycoprotein that functions as a receptor for the extracellular matrix glycan, hyaluronan. It exists as standar d (CD44s) and variant (CD44v) isoforms which have been shown to be ass ociated with metastasis in a range of tumors. Both CD44s and CD44v are found in normal respiratory epithelium and in non small cell lung can cers (NSCLCs). However, there isn't much information regarding their r ole in the metastatic process of NSCLCs. We examined the expression of CD44s in 30 NSCLCs using immunohistochemical techniques. Ten were non -metastatic (N0, M0), 5 were metastases to lymph nodes (N1, M0) and 15 were excised brain metastases. We found CD44s positivity in all non-m etastatic tumors with varying degrees of expression, whereas 10 out of 15 metastatic tumors in brain and 3 out of 5 lymph node metastases we re negative for CD44s. There was a statistically significant inverse r elation between the CD44s expression and metastatic potential (P < 0.0 5). Our results support the hypothesis that diminished or lack of CD44 s is the functional equivalent of CD44v which may be an accompaniment of enhanced metastatic potential. The value of CD44 in predicting meta static behavior of NSCLCs remains to be established in a larger series . (C) 1997 Elsevier Science Ireland Ltd.