Analysis of TP53 germline mutations in pediatric tumor patients using DNA microarray-based sequencing technology

Whereas in sporadic human malignancies mutations of the TP53 tumor-suppressor gene occur in cancers of almost every organ and histologic subtype, patients with an inborn TP53 defect are at high risk to develop, in particular, soft tissue and bone sarcomas, brain tumors, leukaemias, adrenocortical tumors, and breast cancer. To demonstrate the usefulness of microarray technology applied to TP53 sequencing in pediatric tumors, we investigated young patients suffering from tumors typical of the Li-Fraumeni context who were, therefore, candidates for harboring inborn defects in tumor-suppressor genes.

Six individuals were studied, including typical Li-Fraumeni patients as well as patients without any family history of cancer. DNA samples were independently analyzed for TP53 mutations by GeneChip and standard automated laser fluorescence (ALF) sequencing technology.

The tumor and corresponding constitutional DNA samples clearly showed identical mutations which were confirmed by ALF sequencing. All coding exons (exons 2-11) of TP53 were analyzed simultaneously. The entire sequencing procedure and data analysis was carried out within 24 hr.

The GeneChip TP53-sequencing assay may be feasible for routine molecular genetic diagnostics in determining the TP53 status of childhood-tumor patients and in enabling a disease management based on the genetic background of the individual.