Anna Garuti1, Ilaria Rocco1, Gabriella Cirmena1, Maurizio Chiaramondia2, Paola Baccini3, Massimo Calabrese4, Claudia Palermo1, Daniele Friedman5, Gabriele Zoppoli6, Alberto Ballestrero1. 1. Department of Internal Medicine, Istituto di Ricerca a Carattere Clinico e Scientifico (IRCCS), Azienda Ospedaliera Universitaria (AOU) San Martino Istituto Nazionale Tumori (IST), Genoa, Italy. 2. Division of Pathology, Busto Arsizio Hospital, Busto Arsizio, Varese, Italy. 3. Department of Surgical Sciences and Integrated Diagnostics, University of Genoa and Anatomic Pathology Service, IRCCS AOU San Martino IST, Genoa, Italy. 4. Department of Radiology, IRCCS AOU San Martino IST, Genoa, Italy. 5. Breast Surgery Unit, Department of Surgery, University of Genoa and IRCCS AOU San Martino IST, Genoa, Italy. 6. Department of Internal Medicine, Istituto di Ricerca a Carattere Clinico e Scientifico (IRCCS), Azienda Ospedaliera Universitaria (AOU) San Martino Istituto Nazionale Tumori (IST), Genoa, Italy. Electronic address: gabriele.zoppoli@unige.it.
Abstract
OBJECTIVES: Reliable assessment of estrogen, progesterone (ER and PR), and HER2 receptor status are essential in breast cancer (BC) treatment. Immunohistochemical methods are limited by intra- and inter-laboratory variability. Furthermore, current methods are not the ideal approach for reproducing the biological continuum of ER, PR, and HER2 receptor levels, due to their intrinsic, semi-quantitative nature, relying in part on subjective interpretation. METHODS: 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). RESULTS: 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- 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. CONCLUSIONS: 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.
OBJECTIVES: Reliable assessment of estrogen, progesterone (ER and PR), and HER2 receptor status are essential in breast cancer (BC) treatment. Immunohistochemical methods are limited by intra- and inter-laboratory variability. Furthermore, current methods are not the ideal approach for reproducing the biological continuum of ER, PR, and HER2 receptor levels, due to their intrinsic, semi-quantitative nature, relying in part on subjective interpretation. METHODS: 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). RESULTS: 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- 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. CONCLUSIONS: 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.