Natali P G, Nicotra M R, Winkler A B, Cavaliere R, Bigotti A, Ullrich A
Regina Elena Cancer Institute, Rome, Italy.
Int J Cancer. 1992 Sep 9;52(2):197-201. doi: 10.1002/ijc.2910520207.
Mutations at the white spotting (w) locus in mice have deleterious effects on germ cells, melanocytes and hematopoietic stem cells. The w locus encodes the c-kit tyrosine-kinase receptor whose ligand is the product of the SI locus. Using monoclonal antibodies (MAb(s)) to the extracellular domain, we have evaluated the expression of c-kit in normal and transformed melanocytes. This cell lineage synthesizes a receptor with a mw of 145 kDa. The gene product is expressed in epidermal melanocytes and in a fraction of nevocytic and blue nevi. In primary melanomas, loss of the receptor is observed in more invasive lesions. Only 30% of the metastatic lesions express detectable levels of the receptor. These findings demonstrate that the c-kit product is down-regulated in melanocytes following malignant transformation. The functional relevance of this modulation remains to be evaluated.
小鼠白斑（w）位点的突变对生殖细胞、黑素细胞和造血干细胞有有害影响。w位点编码c-kit酪氨酸激酶受体，其配体是SI位点的产物。利用针对细胞外结构域的单克隆抗体，我们评估了c-kit在正常和转化黑素细胞中的表达。该细胞谱系合成一种分子量为145 kDa的受体。基因产物在表皮黑素细胞以及一部分痣细胞和蓝色痣中表达。在原发性黑色素瘤中，在侵袭性更强的病变中观察到受体缺失。只有30%的转移病变表达可检测水平的受体。这些发现表明，c-kit产物在黑素细胞恶性转化后下调。这种调节的功能相关性仍有待评估。
