However, the reverse MR analysis provided evidence that squamous carcinoma elevated cathepsin B levels (IVW: p = 0.0328, OR = 1.189, 95% CI = 1.014–1.395; and weighted median: p = 0.038, OR = 1.224, 95% CI = 1.011–1.481), and the p-values of the MR-Egger intercept and MR-PRESSO global test showing no signs of directional pleiotropy (0.826 and 0.804, respectively) (Supplementary Table 2). Here, CTSB is linked to squamous cell carcinoma.