NQO1 and squamous cell carcinoma: It is important to note that several types of solid tumors, such as cholangiocarcinoma [119], lung [120], pancreas [121], breast [122] and squamous cell carcinoma of the uterine cervix [123], have high expression of NQO1, and there are studies that demonstrate a β-lapachone preferential tropism for NQO1-positive cells [124].