P53 GENE-MUTATIONS ARE RARE IN PATIENTS BUT COMMON IN PATIENT-ORIGINATING CELL-LINES IN MULTIPLE-MYELOMA

We have shown previously that detectable serum concentration of p53 pr otein is associated with poor prognosis in multiple myeloma (MM). In t his study, we studied p53 gene mutations in 29 bone marrow samples of MM patients using polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and direct sequencing. No p53 mutations were found in these patients although 41% of the patients had an elevated s erum p53 protein concentration. This result indicates that the detecta ble serum level of p53 protein is not associated with p53 mutations. I n addition, we have also analysed three MM cell Lines established from bone marrow samples. All the cell lines contained p53 mutations in ex on 5. However, bone marrow samples of the patients associated with the cell lines did not have these mutations at the time of diagnosis, nor did the original samples which were used to establish the cell lines. This indicates that p53 mutations can arise during the cell passages.