Despite the absence of correlation between CLDN1 expression and tumor location (stomach/other localization) (p = 0.34161; two-tailed Fisher’s exact test), gender (female/male) (p = 1.00000; two-tailed Fisher’s exact test), and age (p = 0.59547; Student’s t-test), a significant correlation between CLDN1 expression in GIST specimens and the prognostic group (low risk/intermediate and high risk) was observed (p = 0.02123; two-tailed Fisher’s exact test). This evidence concerns the gene CLDN1 and gastrointestinal stromal tumor.