SNP rs1049430 in the 3'-UTR of SH3GL2 regulates its expression: Clinical and prognostic implications in head and neck squamous cell carcinoma.

Single nucleotide polymorphisms (SNPs) in the 3'-UTR region are emerging cis-regulatory factors associated with the occurrences of several human diseases. SH3GL2, which is located at chromosome 9p21-22, is associated with hyperplastic/mildly dysplastic lesions of the head and neck and has a long 3'-UTR with multiple SNPs. The aim of the present study was to determine the susceptible allele(s) in the 3'-UTR SNPs of SH3GL2 in head and neck squamous cell carcinoma (HNSCC). First, we screened the genotypes of all SNPs located in the 3'-UTR of SH3GL2 in 110 controls and 147 cases in Indian populations by sequencing. A SNP (rs1049430:>G/T) that showed only heterozygosity was further confirmed by genotyping with an Illumina GoldenGate platform in 530 controls and 764 cases. Genotype-specific survival analysis of the HNSCC patients was performed. In addition, genotype-specific mRNA stability, isoform expression and protein expression were analyzed. SNP rs1049430 was not associated with disease occurrence, but it was associated with poor patient outcome. The G allele was associated with decreased SH3GL2 mRNA stability, differential splicing and low protein expression. Thus, our data demonstrate that the presence of the susceptible G allele in SNP rs1049430 is associated with the inactivation of SH3GL2 and could be used as a prognostic marker of HNSCC.