Given that expression of the lung-specific isoform (CLDN18.1) is markedly decreased in LUAD and that aged Cldn18 -/- mice have an increased propensity to develop LUAD, CLDN18.1 was assumed to have a tumour suppressor role in LUAD, and this was validated by Luo et al. This evidence concerns the gene CLDN18 and neoplasm.