ANALYSIS OF THE P16(INK4A), P15(INK4B) AND P18(INK4C) GENES IN MULTIPLE-MYELOMA

To study the structural integrity of the cyclin-dependent kinase inhib itors known as INK4A (p16), INK4B (p15) and INK4C (p18) in multiple my eloma, we examined 20 primary myeloma samples (including one case of p lasma cell leukaemia) using polymerase chain reaction-single strand co nformation polymorphism, and 17 samples were examined by Southern blot analysis. The plasma cell leukaemia sample had homozygous deletions o f the p15 and p16 genes (6%). One myeloma case had a p15 gene homozygo us deletion (6%) with an intact p16 gene. This sample also had a p18 h omozygous deletion, suggesting that the deletion of both genes may be important in either the development or progression of myeloma. No poin t mutations of these INK4 genes were found in the 20 samples. This is the first report that indicates that deletions of p15, p16 and p18 gen es occur in some individuals with multiple myeloma (2/17 cases).