A common background factor of these cancers is the availability of non-invasive tests (ie, PSA for prostate cancer and ultrasonography for thyroid cancer).11,26,58–61 In addition to this descriptive approach, empirical or modelling approaches that compare screened and unscreened (or tested and untested) populations are needed to quantitively examine overdiagnosis.62 Despite the possibility of overdiagnosis, both prostate and thyroid cancers showed significant decreases in mortality. This evidence concerns the gene KLK3 and cancer.