The full-length cDNA sequence of a novel gene PROL4 was obtained through suppression subtraction hybridization and cDNA microarray technique between NPC biopsies and normal adult nasopharyngeal epithelial tissue. PROL4 gene whose GenBank accession number was AF530472 consisted of 567 bp and coding 134 amino acids. RT-PCR confirmed that PROL4 gene was down-expressed in NPC cell line HNE1 and NPC biopsies (42/48). As it was shown by Northern blot, PROL4 gene was expressed in skeletal muscle, thymus and lung, whose transcription size was about 0.6 kb. The expression profiling was further tested by Cancer Profiling Array hybridization in multiple cancer tissues such as breast carcinoma, uterus carcinoma, colon carcinoma, stomach carcinoma, ovary carcinoma, lung carcinoma, kidney carcinoma, rectum carcinoma, thyroid carcinoma, cervix carcinoma, prostate carcinoma, pancreas carcinoma and small intestine carcinoma.