During tumor progression, higher levels of KLK7 in tumor tissue have been mainly associated with poor prognosis in a variety of cancer types, even when the expression level was found to be downregulated in relation to the corresponding nonmalignant, normal tissue (Devetzi et al., 2013; Kryza et al., 2016; Stefanini et al., 2015). This evidence concerns the gene KLK7 and cancer.