• Hallmark of cancer (Hanahan and Weinberg, 2011; Vaupel et al., 2019)• Regulated by HIF-1α, which controls expression of LDHA (Ivan et al., 2001; Jaakkola et al., 2001; Kaluz et al., 2006)• LDHA is a poor prognostic indicator and correlated to increased tumor size (Koukourakis et al., 2003; Koukourakis et al., 2005; Kolev et al., 2008)• Lactate accumulates within the tumor microenvironment (Walenta and Mueller-Klieser, 2004). The gene discussed is LDHA; the disease is cancer.