EXPRESSION OF THE C-KIT RECEPTOR AND ITS LIGAND SCF IN NON-SMALL-CELLLUNG CARCINOMAS

Increasing experimental evidence indicates that stem-cell factor (SCF) and its cognate receptor c-Kit may participate in the growth control of various solid human malignancies, In the present study, we have ext ended this analysis to non-small-cell lung carcinomas (NSCLC). The res ults of an immunohistochemical analysis demonstrated that c-Kit/SCF ar e expressed by 30%/58% of adenocarcinomas, 15%/37% of squamous-cell ca rcinomas and by 40%/30% of undifferentiated carcinomas respectively. I n 15% of primary and 18% of metastatic tumors, co-expression of the re ceptor and its ligand was documented, Western-blot assays of tumor ext racts demonstrated that both molecules exhibit features of the normal receptor and ligand. Since biologically active SCF is physiologically present in the bloodstream, our data indicate that SCF is available to c-kit-expressing NSCLC cells via autocrine, paracrine or endocrine me chanisms, Thus activation of c-Kit in these tumors may contribute crit ically to their progression. (C) 1998 Wiley-Liss, Inc.