It was reported that knockdown of Mucin-like 1 (MUCL1) in HER2-amplified breast cancer resulted in FAK/Jun NH2-terminal kinase (JNK) signaling blockade and subsequent G1/S phase arrest, which was mediated by decreased cyclin D levels as well as increased p21 and p27 levels [54]. This evidence concerns the gene MUCL1 and breast cancer.