Medline/Pubmed articles relevant to this topic were considered using the search terms ?-microseminoprotein, MSMB, prostate secretory protein of 94 amino acids and PSP94. Full articles were retrieved when the abstract was considered relevant. In addition, other data related to this topic including our own are discussed. Summary of fi ndings-?-microseminoprotein(MSMB) is increasingly being considered as a marker for prostatecancer, as reduced levels have been associated with the disease. Here we review various aspects of this protein including its biological and physiological variants, binding proteins and immune modulation; its importance as a marker for biochemical recurrence of prostate cancer; prostate cancer related splice variants and its therapeutic utility. Two of the most important properties of MSMB are related to anticancer functions and immune modulation. Predominant expression of two(short and full-length) splice variants of MSMB has been observed from normal prostate and several other tissues. In benign prostate hyperplasia the short isoform is dominant, constituting 98% of this isoform, whereas in prostate cancer 96% constitute the fulllength isoform. The MSMB promoter single nucleotide polymorphism rs10993994 with the C allele functions as an activated cyclic adenosine monophosphate response element binding protein binding site. This C variant of rs10993994 could be responsible for the production of splice variants under variable conditions. MSMB has binding motifs to a few known proteins including immunoglobulin G and several Cysteine-rich secretory proteins family proteins. MSMB bound to these proteins is considered as immune modulating. Use of MSMB as a urinary marker for detecting aggressive prostate cancers that could resist radiation and surgical treatments, seems possible, but needs further investigation. The ratio of MSMB splice variants could also be a possible approach in understanding prostate cancers, with higher ratios indicating severe disease. Medline / Pubmed articles relevant to this topic were considered using the search terms? -microseminoprotein, MSMB, prostate secretory protein of 94 amino acids and PSP94. Full articles were retrieved when the abstract was considered relevant. In addition, other data related to this topic Here we review various aspects of this protein, including its biological and physiological, as reduced standard has been associated with the disease. variants, binding proteins and immune modulation; its importance as a marker for biochemical recurrence of prostate cancer; prostate cancer related splice variants and its therapeutic utility. Two of the most important properties of MSMB are related to anticancer functions and immune modulation. two (short and full-length) splice variants of MSMB has been observed from normal prostate and se ve the other tissues. In benign prostate hyperplasia the short isoform is dominant, consisting of 98% of this isoform, while in prostate cancer 96% the fulllength isoform. The MSMB promoter single nucleotide polymorphism rs10993994 with the C allele functions as an activated cyclic adenosine monophosphate response element binding protein binding site. This C variant of rs10993994 could be responsible for the production of splice variants under variable conditions. MSMB has binding motifs to a few known proteins including immunoglobulin G and several Cysteine-rich secretory proteins family proteins. these proteins is considered as immune modulating. Use of MSMB as a urinary marker for detecting aggressive prostate cancers that could resist radiation and surgical treatments, seems possible, but needs further investigation. The ratio of MSMB splice variants could also be a possible approach in understanding Prostate cancers, with higher ratios indicating severe disease.