Tumour cell‐to‐cell interactions could be involved, but do not appear to be the most obvious explanation based on the result in the current study, as AT1 cell growth in vitro was unaffected when co‐cultured with MLL or AT1 cells in a Transwell assay, and AT1‐CM was equally effective as MLL‐CM in stimulating AT1 cell growth. Here, KMT2A is linked to neoplasm.