Testicular germ cell tumor comprises about 1% of all the
malignancies of males in Japan, and occurs in only one over 100,000 males annually. A susceptibility gene may be located on the short arm of the chromosome 12. Among the genes in this region, the expression of the KRAS2
mRNA was increased in
testicular cancer compared to the normal testicular tissue. By DNA typing,
HLA-DR4 and 0405 allele in
HLA-DRB1 showed high relative risk for
testicular cancer. We analyzed the expression of the WT1 gene, reported to be a growth promoter for
leukemia, by quantitative reverse transcription-PCR. Relative expression of the WT1 gene was significantly increased in high-stage cases than in low-stage cases, suggesting that WT1 could be useful as a
tumor marker for progression of
testicular cancers. Testicular
germ cell tumors are usually very sensitive to chemotherapeutic agents such as
cisplatin, and p53 has been reported to play an important role in chemosensitivity. Therefore, mutations of the p53 gene or other genes downstream may be responsible for their chemoresistance. The expression of the GML (GPI--anchored molecule like
protein) gene was examined in
testicular cancers. Its expression was not correlated with histology or stage. However, 4 refractory cases, 2 of which were recurrent cases from stage I and the others were at high stages, showed no expression of the GML
mRNA. These interesting facts suggest that the expression of GML gene could be a good marker for the prognosis of testicular
germ cell tumors.