OBJECTIVE: Heat shock protein 70-2 (Hsp70-2) gene knockout mice are found to have premeiotic arrest at the primary spermatocyte stage with a complete absence of spermatids and spermatozoa. This observation led to the hypothesis that hspA2 may be disrupted in human testes with abnormal spermatogenesis. To test this hypothesis, we studied the mRNA expression of hspA2 in infertile men with azoospermia. DESIGN: The mRNA expression were analyzed by competitive RT-PCR among testes with normal spermatogenesis, pachytene spermatocyte arrest, and sertoli-cell only syndrome. MATERIALS AND METHODS: Testicular biopsy was performed in men with azoospermia (n=15). Specimens were subdivided into three groups: (group 1) normal spermatogenesis (n=5), (group 2) spermatocyte arrest (n=5), (group 3) Sertoli-cell only syndrome (n=5). Total RNA was extracted by Trizol reagent. Total extracted RNA was reverse transcribed into cDNA and amplified by PCR using specific primers for hspA2 target cDNAs. A competitive cDNA fragment was constructed by deleting a defined fragment from the target cDNA sequence, and then coamplified with the target cDNA for competitive PCR. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene was used as an internal control. RESULTS: On Competitive RT-PCR analyses for hspA2 mRNA, significant amount of hspA2 expression was observed in group 1, whereas a constitutively low level of hspA2 was expressed in groups 2 and 3. CONCLUSION(S): The study demonstrates that the hspA2 gene expression is down-regulated in human testes with abnormal spermatogenesis, which in turn suggests that hspA2 gene may play a specific role during meiosis in human testes.