Expression of proteins correlated with the unique cisplatin-sensitivity of testicular cancer

Cisplatin (CDDP) has a curative effect in approximately 80% of patients with testicular cancer, in contrast to the frequent development of resistance in patients with small cell lung cancer and ovarian cancer, and to the natural resistance of colon cancer. At present it is unknown which factors explain the unique curability of testicular cancer. Since it is very likely that the absence or presence of specific proteins plays an important role in cellular sensitivity towards CDDP, we have screened the protein patterns of various human CDDP-sensitive cell lines and cell lines with acquired or intrinsic resistance to CDDP of testicular, lung and colon origin. The expression of several proteins appeared to correlate with in vitro CDDP sensitivity. The most striking difference found was a relative increase in expression lactate dehydrogenase (LDH) H-subunit expression in the germ cell lines. In testis and colon tumour samples some of these proteins, LDH-H included, also appeared to correlate with in vivo CDDP sensitivity. In the analysis of the mechanisms of drug-resistance, screening of the protein patterns of intrinsic sensitive and resistant cell lines could be a valuable approach.