Possible involvement of the chromosome region 10q24----q26 in early stages of melanocytic neoplasia.

A recent report described a translocation involving 10q24 in a compound nevus. We have examined our series of melanocytic tumors ranging from common nevi to metastatic melanomas with the following results. In 24 nevi (congenital or common acquired), no karyotypically abnormal clones were found. Two of 10 dysplastic nevi had abnormal clones: one had an unidentified marker chromosome, the other had a t(9;10)(p24;q24) translocation. Of the three complex primary melanomas studied (lesions with both radial and vertical growth phase present), one had a t(10;?)(q26;?) and one showed a loss of chromosome 10. Among 51 advanced melanomas (primary and metastatic), all but one had multiple alterations, and 18 of these had lost one or more copies of chromosome 10. The one invasive melanoma without multiple abnormalities had a complex three-way rearrangement: 46,XY,t(5;6;10) with breakpoints on chromosome 10 at both q23 and q25. These data support the view that the terminal region of 10q may harbor one or more genes involved in the early stages of melanocytic neoplasia.