We hypothesized that environmental carcinogens might be the potential effector driving the protective or oncogenic role of rs32000401 polymorphisms in cancers, because our study showed that OSCC patients harboring at least one T allele of MALAT1 rs3200401 were at a lower risk of developing lymph node metastasis if they did not chew betel nut. Here, MALAT1 is linked to cancer.