We found that PCDH8, which acts as a tumor-suppressor gene in multiple types of cancer and inhibits tumor cell proliferation, invasion and migration (Yu et al., 2020), was downregulated in clusters 3 and 4 (Figures 2C,D), suggesting that tumor cells may be more aggressive in the two clusters with lower PDCH8 expression. The gene discussed is PCDH8; the disease is cancer.