Mutational analysis of proto-oncogene Dbl on Xq27 in testicular germ cell tumors reveals a rare SNP in a patient with bilateral undescended testis.
OBJECTIVE
An abundance of X chromosomes in testicular germ cell tumors (TGCTs), and a candidate TGCTs susceptibility gene (TGCT1) on Xq27 highlight the potential involvement of X chromosomes in TGCT pathogenesis. However, the TGCT1 on Xq27 has so far not been identified. We hypothesized that a somatic mutation of dbl oncogene on Xq27 may play a role for the development of TGCTs.


METHODS
We have screened 41 TGCT tissues for dbl mutations using single-strand conformation polymorphism (SSCP) analysis. These tissues are composed of 25 seminomatous TGCTs tissues and 16 non-seminomatous TGCTs tissues, including two cases with a rhabdomyosarcoma component.


RESULTS
Somatic mutations were not detected in the 25 exons of dbl in these TGCTs. However, we found a rare single nucleotide polymorphism (SNP) (T to C nucleotide change) within intron 22 in one out of the 41 TGCTs cases (2%). Furthermore, the sample with the rare SNP was identified as the sole TGCTs case associated with bilateral undescended testis in our series.


CONCLUSIONS
Our results indicate that proto-oncogene dbl is not a major target for sporadic TGCTs. However, the rare SNP in dbl may affect the susceptibility to undescended testis. Determining the frequency of this SNP in patients with various types of undescended testis in different ethnic groups is a warranted study.
Department of Urology, First and Fourth AYliated Hospital, Harbin Medical University, 150001 Harbin, Heilongjiang, China.
Wan-Hai
WH
Xu
Cheng
C
Zhang
Wei-Ming
WM
Zhao
Chun-Mei
CM
Li
You-Cheng
YC
Xiu
Shao-Bin
SB
Ni
Ming-Hua
MH
Ren
Dian-Jun
DJ
Sun
D041321:Chromosomes, Human, X; D003456:Cryptorchidism / Q000235:genetics*; D004252:DNA Mutational Analysis; D020022:Genetic Predisposition to Disease; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics*; D006801:Humans; D008297:Male; D009373:Neoplasms, Germ Cell and Embryonal / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D018807:Polymorphism, Single-Stranded Conformational; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D013736:Testicular Neoplasms / Q000235:genetics*
D020662:Guanine Nucleotide Exchange Factors; C000715470:MAS1 protein, human; C057811:MCF2 protein, human; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins