Lee et al. (2020) observed that MAMDC2 expression was down-regulated in breast cancer and that the overexpression of MAMDC2 significantly inhibited the proliferation of breast cancer T-47D cells, which may act by attenuating the MAPK signaling pathway. Unfortunately, we did not find any experimental reports of ABCA8 and MAMDC2 associated with GC. In addition, since our results showed that COL6A3 (Collagen Type VI Alpha 3 Chain) and TMEM266 (Transmembrane Protein 266) had low AUC values in the validation set and poor diagnostic efficacy and stability, we will not elaborate on them here. The gene discussed is TMEM266; the disease is breast cancer.