An isolated polynucleotide at least 60% homologous to SEQ ID NO: 1, 3, 5 or 18 encoding a SARP polypeptide; vectors comprising a polynucleotide sequence encoding at least 11 consecutive amino acids of SARP polypeptide; a host cell transformed with an isolated polynucleotide or vector; antibodies specific for SARP and use of such polynucleotides and antibodies in diagnostic and therapeutic method. Therapeutic uses of antibodies and polynucleotides of sarp. Methods for treating diseases related to the regulation of SARP expression in tissue and bodily fluid samples, including cancers.