Codon 201Gly Polymorphic Type of the DCC Gene is Related to Disseminated Neuroblastoma

Abstract

The deleted in colorectal carcinoma (DCC) gene is a potential tumor- suppressor gene on chromosome 18821.3. The relatively high frequency of loss of heterozygosity (LOH) and loss of expression of this gene in neuroblastoma, especially in the advanced stages, imply the possibility of involvement of the DCC gene in progression of neuroblastoma. However, only few typical mutations have been identified in this gene, indicating that other possible mechanisms for the inactivation of this gene may exist. A polymorphic change (Arg to Gly) at DCC codon 201 is related to advanced colorectal carcinoma and increases in the tumors with absent DCC protein expression. In order to understand whether this change is associated with the development or progression of neuroblastoma, we investigated codon 201 polymorphism of the DCC gene in 102 primary neuroblastomas by polymerase chain reaction single-strand conformation polymorphism. We found no missense or nonsense mutations, but a polymorphic change from CGA (Arg) to GGA (Gly) at codon 201 resulting in three types of polymorphism: codon 201Gly type, codon 201Arg/Gly type, and codon 201Arg type. The codon 201Gly type occurred more frequently in disseminated (stages IV and IVs) neuroblastomas (72%) than in localized (stages I, II, and III) tumors (48%) (P=.035), and normal controls (38%) (P=.024). In addition, the codon 201Gly type was significantly more common in tumors found clinically (65%) than in those found by mass screening (35%) (P=.002). The results suggested that the codon 201Gly type of the DCC gene might be associated with a higher risk of disseminating neuroblastoma.

Keywords

• tumor -suppressor gene
• the DCC gene
• PCR-SSCP
• codon 201 polymorphism
• neuroblastoma