LAPTM4B gene polymorphism augments the risk of cancer: Evidence from an updated meta‐analysis

Lysosome‐associated protein transmembrane‐4 beta (LAPTM4B) has two alleles named as LAPTM4B*1 and LAPTM4B*2 (GenBank No. AY219176 and AY219177). Allele *1 has a single copy of a 19‐bp sequence in the 5` untranslated region (5`UTR), but allele *2 contains tandem repeats of 19‐bp sequence. LAPTM4B gene is located on long chromosome 8 (8q22.1) and contains seven exons that encodes two isoforms of tetratransmembrane proteins, LAPTM4B‐24 and LAPTM4B‐35, with molecular weights of 25 kDa and 35 kDa respectively. The LAPTM4B‐35′s primary structure is formed by 317 amino acid residues, and LAPTM4B‐24 comprised 226 amino acids. LAPTM4B, an integral membrane protein, contains several lysosomal‐targeting motifs at the C terminus and colocalizes with late endosomal and lysosomal markers. LAPTM4B is a proto‐oncogene, which becomes up‐regulated in various cancers. Preceding studies have examined the possible link between LAPTM4B polymorphism and susceptibility to several cancers,but the findings are still inconsistent. Hence, the present meta‐analysis was designed to investigate the impact of LAPTM4B polymorphism on risk of cancer.