Biomarkers of chemotherapy-induced testicular damage.

Increasing numbers of men are having or wanting children after chemotherapy treatment. This can be attributed to improvements in cancer therapies that increase survival. However, a side effect of most chemotherapy drugs is disruption of spermatogenesis and a drastic reduction in sperm count and quality. Although many men eventually recover reproductive function, as indicated by normal semen analyses, there is no clinical test that can assess sperm quality at a high level of sensitivity. Sperm fluorescent in situ hybridization (i.e., FISH) and several different tests for deoxyribonucleic acid (DNA) fragmentation have been used infrequently in clinical assessment. Animal models of chemotherapy-induced testicular damage are currently being used to identify potential molecular biomarkers that may be translatable to humans-these include sperm messenger RNAs, microRNAs, histone modifications, and DNA methylation patterns. Changes in these molecular measurements are quantitative and sensitive, potentially making them important clinical biomarkers of testicular function after chemotherapy treatment.