Background: The aim of this study was to assess the usability of multiplex ligation-dependent probe amplification (MLPA) for copy number determination of
HER gene family members (
ERBB1-4) in invasive breast carcinoma and to explore the association of
ERBB1-4 gene copy numbers with clinicopathological characteristics of breast cancer (BC) patients.
Methods: Clinical and immunohistochemical characteristics were assessed in 104 BC patients and the molecular subtype was determined for each tumor sample. Furthermore, HER-2/neu status was assessed by immunohistochemistry (IHC) and equivocal results were confirmed by Fluorescent in situ hybridization (FISH). The copy numbers of
ERBB1-4 genes were determined by MLPA.
Results: Twenty-five percent of all patients showed
ERBB2 gene-amplification by MLPA, whereas 14.4% of cases showed
ERBB-2/neu overproduction at the protein level (IHC). Moreover, only 2.9% and 1.9% of patients showed amplification in
ERBB1 and
ERBB4, respectively. No copy number changes were observed in
ERBB3. Our results indicated a significant association between
ERBB2 copy number gain and histological grade (
p value= 0.01), stage (
p value= 0.02), and tumor subtypes (
p value= <0.001). In addition, we found MLPA more accurate in assessing
HER2 status with 15.4% and 9.6% gene amplification detection in early stages (1, 2A and 2B) and advanced tumor stages (3A, 3B, and 4), respectively, compared to IHC (early stages= 13.5% and advanced stages= 4.7%).
Conclusions: According to our findings, MLPA is a fast, precise and low-cost technique to detect
ERBB2 amplification, especially in advanced tumor stages. However, due to infrequent amplification found in
ERBB1 and
ERBB4 as well as the lack of amplification in
ERBB3, their importance in the prognostic evaluation of BC patients remains controversial.