['TR-KIT, a truncated form of KIT (the KITL receptor), corresponding to the c-terminal half of the intracellular split tyrosine kinase domain, is expressed during the haploid stages of mouse spermatogenesis, and is one of the candidate sperm factors possibly involved in egg activation at fertilization.', 'Immunocytochemistry of adult human testis, and studies of human semen samples from volunteer donors through immunofluorescence, confocal microscopy, flow cytometry, western blot and RT-PCR analyses were performed.', "We show that the TR-KIT is expressed during spermiogenesis in the human testis, and that it is maintained in human ejaculated spermatozoa. TR-KIT is localized both in the equatorial segment and in the sub-acrosomal region of the human sperm head. The equatorial localization of the TR-KIT persists after the spontaneous acrosome reaction. Cytometric analysis of several sperm samples from volunteer donors, showed variable degrees of the TR-KIT-specific immunolabeling, and a significant inverse correlation (Pearson's coefficient, r = -0.76, P < 0.0001, n = 23) of the TR-KIT positivity with markers of sperm damage, i.e. DNA fragmentation, as revealed by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-nick end labeling (TUNEL) analysis and the intense clusterin positivity. We also found less significant inverse correlation with altered head morphology (r = -0.47, P < 0.05, n = 23) and direct correlation with sperm forward motility parameters (r = 0.59, P < 0.01, n = 23)."] Does expression of a truncated form of KIT tyrosine kinase in human spermatozoa correlate with sperm DNA integrity?