Objective: To clarify the role of one of the downstream effectors of Rho (Rho-kinase) in testicular germ cell tumour (GCT) by quantifying mRNA expression for Rho-kinase in patients with this disease.
Materials and methods: The mRNA levels of the RhoA and Rho-kinase genes were analysed in surgical specimens of testicular GCT tissues from 57 consecutive Japanese patients, and in the corresponding non-tumour tissue originating from the same patient, using the polymerase chain reaction after reverse transcription. The expression levels of these genes were compared between the tissues and the relationship between their expression levels evaluated within tumours and with tumour stage. The difference in the expression levels of the mRNAs of RhoA and Rho-kinase genes were also assessed between tumours that were seminoma only and mixed tumours of seminoma and nonseminoma.
Results: RhoA and Rho-kinase mRNAs were more abundant in tumour tissue than in non-tumour tissue (P < 0.01 and < 0.05, respectively). High RhoA and Rho-kinase mRNA expressions were related to tumour stage (P < 0.05 and < 0.01, respectively). The mRNA levels of RhoA and Rho-kinase in mixed tumours were higher than in tumours with seminoma only (P < 0.01 and < 0.05, respectively). There was a positive relationship between expression levels of mRNAs of RhoA and Rho-kinase in tumour tissues (P < 0.001).
Conclusions: These findings suggest that the RhoA/Rho-kinase pathway is involved in the progression of testicular GCT. This pathway might be a molecular target for new treatment strategies for this disease.