LOXL4 and hepatocellular carcinoma: For example, an increase in TAMs induced by lysyl oxidase-like 4 (LOXL4: a copper-dependent monoamine oxidase in the extracellular matrix) in mice is primarily attributable to monocyte infiltration; LOXL4 is capable of suppressing the proliferation of resident liver macrophages and nearly eliminating them during the development of HCC [32].