CA4 and cancer: In vitro, drug release tests at acidic conditions (pH 5.5 and 5.5, mimicking tumor microenvironment) and physiological conditions (pH 7.4, 37 °C) exhibited a pH-responsive CA4 release manner from nanoliposomes because higher levels of CA4 were released at pH 5.5 and pH 6.5 than at pH 7.4, indicating that CA4-encapsulated nanoliposomes can lead to superior cytotoxicity against cancer than in normal cells.