Real-time PCR: detection of oestrogen receptor-alpha and -beta isoforms and variants in breast cancer

Splice variants exist for both alpha and beta oestrogen receptors (ERs). Oestrogen function results from a balance between the wild-type ERs (wt) and their variants.

Forty formalin-fixed paraffin-embedded breast cancer samples were analysed by real-time PCR using ERα primer sets detecting wt and exon-deleted 3, 5, 6 and 7 variants. The ERβ primer sets detected wt ERβ1 and ERβ2 and ERβ5 variants. At the end of the PCR cycles, a dissociation curve was generated showing the peaks for each sample at specific melting temperatures (Tm); finding more than one peak indicated the presence of variants.

Many samples expressed both wt ER isoforms and their variants. The Tm value served as a cut-off point for determination of wt versus variant ER expression.

This method of detection of wt and variant ER could help in patient selection for anti-oestrogen therapy and in monitoring response to therapy.