In the present study, we tested a molecular approach to define ER, PR, and HER2 status in fine-needle-aspirate (FNA) samples from patients with early BC. We performed flow cytometry analysis on 88 FNA specimens from suspect BC patients to determine cellularity. We used quantitative Real Time PCR (QRT-PCR) to assess ER, PR, HER2 status, and qPCR for HER2 gene copy number (GCN).
ER and PR mRNA levels showed a highly significant correlation with IHC data on surgical samples. qPCR showed greater accuracy than IHC in defining HER2 status. QRT-PCR defined better than IHC the continuous spectrum of the expression of the assessed receptors. Moreover, PCR analysis demonstrated a strict correlation between HER2 status and higher levels of its transcript, correctly stratifying HER2 + and HER2 鈭?patients. Finally, there was a strongly significant agreement between HER2 GCN assessed on FNA specimens by qPCR and FISH data obtained on pathological tissue specimens.
The present results support a comprehensive approach to determine ER, PR, and HER2 status by PCR (QRT-PCR and qPCR) in FNA specimens, with high relevance for therapeutic strategies like neoadjuvant treatment.