PCDH20 and breast cancer: 43, 44. In addition, other members of the PCDH superfamily have been shown to have tumor suppressor activity, such as PCDH17 and PCDH8 in breast cancer 45, 46, and PCDH20 in nasopharyngeal carcinoma 47. Moreover, previous studies have identified that PCDHs are candidate tumor suppressors that modulate regulatory pathways critical in development and disease, such as canonical Wnt signaling 45, 47, 48.