In addition, further single-cell RNA sequencing of trastuzumab resistance patients has also been performed (Wang et al. 2019b), where studies have shown that perhaps a combination of inhibitors targeting CDK4/6 inhibitor-resistant tumours are required, specifically those targeting a immunosuppressive immature myeloid cell (IMC) population in resistant tumours (Wang et al. 2019b). This evidence concerns the gene CDK4 and neoplasm.