HK2 and breast carcinoma: Palmieri et al. found that in vitro, HK2 mRNA and protein levels were elevated in a brain metastatic derivative (231-BR) of the human breast carcinoma cell line MDA-MB-231 relative to the parental cell line (231-P); knocking down HK2 expression in 231-BR cells using a short hairpin RNA reduced their proliferation rate [7].