[Relationship between expression of c-myc and p53 in liposarcoma]

The relationship between liposarcoma and gene c-myc and p53 is not clear. There are also different reports on p53 mutation in liposarcoma. This study was designed to investigate the relationship between the expression of c-myc and p53 genes and liopsarcomas. We hope to better understand the role of the c-myc and p53 genes in molecular biology.

Immunohistochemical labelled streptavidin-biotin (LSAB) method, single strand conformation polymorphism analysis of polymerase chain reaction products (PCR-SSCP), and DNA sequencing were used.

38.09% (16/42) liposarcoma samples detected were immunohistochemically c-myc protein positive. p53 protein was detected in 52 liposarcomas with the positive staining rate of 48.08% (25/52). In different subtypes of liposarcomas, the positive staining rates of c-myc and p53 gene proteins were much lower in well-differentiated liposarcomas than in the poorly differentiated liposarcomas. There was a positive correlation between c-myc and p53 expression in liposarcoma. There was no statistical significance for the different positive staining rate of c-myc and p53 protein in the primary and the recurrent liposarcoma. Abnomality in the single-stranded DNA pattern was determined by PCR-SSCP analysis in 2 samples (pleomophic liposarcomas). Missense mutation in exon 8 of codon 268 of p53 gene (AAC-->ATC) were detected by DNA sequencing. Another heterozygotic cosense mutation may exist at exon 6 of codon 221 of p53 gene (GAG-->GAA).

The c-myc and p53 protein are associated with the development, differentiation, and malignancy of liposarcoma, but not with the recurrence of liposarcoma. Detecting the level of c-myc and p53 protein expression may be valuable in evaluating the level of differentiation and malignancy of liposarcoma. c-myc and p53 play synergic roles in the cooperation of development of liposarcoma. There appear the point mutation on exon 8, 6 of p53 gene.