Therefore, prior to reporter gene assays, we examined whether mRNA transcripts for 5-HTT, glucocorticoid receptor (GR) and estrogen receptor (ER) are expressed in human colon carcinoma cell lines, SW480 and HT-29, using the reverse transcription-polymerase chain reaction (RT-PCR) method for evaluating an appropriate cell model. Here, ESR1 is linked to colon carcinoma.