Poly(rC)-binding protein 1, also known as Heterogeneous nuclear ribonucleoprotein E1, Alpha-CP1, Nucleic acid-binding protein SUB2.3 and PCBP1, is a family member of heterogeneous nuclear ribonucleoproteins (hnRNPs) that belong to RNA-binding proteins and bear three KH domains. PCBP1 is loosely bound in the nucleus. It may shuttle between the nucleus and the cytoplasm. It is abundantly expressed in skeletal muscle, thymus and peripheral blood leukocytes while a lower expression is observed in prostate, spleen, testis, ovary, small intestine, heart, liver, adrenal and thyroid glands. PCBP1 is widely expressed in many human tissues and involved in regulation of transcription, transportation process, and function of RNA molecules. PCBP1 plays a pivotal role in post-transcriptional regulation for RNA metabolism and RNA function in gene expression. PCBP1 acts as a negative regulator of CD44 variants splicing in HepG2 cells, and loss of PCBP1 in human hepatic tumor contributes to the formation of a metastatic phenotype.