Variants of MUC5B minisatellites and the susceptibility of bladder cancer.

The human MUC5B gene, which is primarily expressed in the tracheobronchial tract, is clustered to chromosome 11p15.5 with three other secreted gel-forming mucins, MUC6, MUC2, and MUC5AC. In this study, we identified seven variable number of tandem repeats (VNTRs; minisatellites) from the entire MUC5B region. Six (MUC5B-MS1, -MS2, -MS3, -MS4, -MS5, and -MS7) of the seven minisatellites evaluated in this study were novel minisatellites, but the MUC5B-MS6 minisatellite was described in a previous study. These minisatellites of MUC5B were analyzed in genomic DNA extracted from controls, cancer patients, and multigenerational families. Three (MUC5B-MS3, -MS6, and -MS7) of the seven minisatellites were found to be polymorphic and transmitted through meiosis following Mendelian inheritance in seven families; therefore, these minisatellite polymorphisms could be useful as markers for paternity mapping and DNA fingerprinting. In addition, we evaluated allelic variation in these minisatellites to determine if such variation affected the susceptibility to various carcinomas. To accomplish this, we conducted a case-control study in which the genomic DNA of 789 cancer-free controls and cancer patients with five types of cancer were compared. A statistically significant association between the long rare MUC5B-MS6 alleles and the occurrence of bladder cancer was identified in the younger group (<60; odds ratio, 4.54; 95% confidence interval, 1.0-20.7; p=0.03). This observation suggests that the long rare MUC5B-MS6 alleles evaluated in this study could be used to identify the risk of bladder cancer.