KLK2 and neuroendocrine carcinoma: Further, using RT-PCR, we validated that other AR regulated genes such as KLK2 and TMPRSS2 are also down-regulated in C4-2BER, DKD and NCI-H660 (a representative de novo neuroendocrine cell line from ATCC), and some of the features of t-NEPC have high similarity with this de novo neuroendocrine cancer cell line (Fig. S1D).