Application of Multiplex Ligation-Dependent Probe Amplification in Determining the Copy Number Alterations of Gene Family Members in Invasive Ductal Breast Carcinoma.

BACKGROUND

The aim of this study was to assess the usability of multiplex ligation-dependent probe amplification (MLPA) for copy number determination of gene family members () in invasive breast carcinoma and to explore the association of 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 genes were determined by MLPA.

RESULTS

Twenty-five percent of all patients showed 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 and , respectively. No copy number changes were observed in . Our results indicated a significant association between copy number gain and histological grade (= 0.01), stage (= 0.02), and tumor subtypes (= <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%).

CONCLUSION

According to our findings, MLPA is a fast, precise and low-cost technique to detect amplification, especially in advanced tumor stages. However, due to infrequent amplification found in and as well as the lack of amplification in , their importance in the prognostic evaluation of BC patients remains controversial.