HRH4 and endometrioid adenocarcinoma: Wang et al. showed a statistically significant increase in the transcriptive activity of HRHS and HRH2 with a simultaneous almost-complete silencing of the expression of HRH3 and HRH4 (HRH1 > HRH2 > HRH3 > HRH4) in the HEC-1 endometrioid adenocarcinoma cell line [22].