DSPP and thyroid tumor: In contrast, the absent‐to‐basal level expression of MMP20 and DSPP in normal prostate and thyroid compared to elevated levels in their neoplastic counterpart (see Figures 1 and 2) suggests that the duct epithelial system in normal prostate and the ductless thyroid gland epithelium may be of the less metabolically active type physiologically, mirroring that of metabolically inactive lacrimal duct epithelium.34 In this context, the elevated levels of MMP20 and DSPP in prostate and thyroid neoplasms may be of diagnostic and prognostic utility.