Abstract 1794: A comparative microRNA expression analysis in breast cancer and melanoma tissues

Abstract Recently studies have revealed that a subset of microRNAs (miRNAs) is aberrantly expressed in the development and progression of a variety of cancers including breast cancer and melanoma. Several miRNAs have been implicated in tumorigenesis and progression of human cancer. However, the underlying mechanisms in different types of cancers remain largely unknown. The aim of the study was to compare the expression profiled of miRNA between breast cancer and melanoma patient’s tissues. Methods: Expression levels of 7 miRNAs (miR-15b, miR-142-3p, miR-142-5p, miR-142a, miR-199a, miR-221, miR-424, ) were determine in 17 cases of breast cancer and 25 melanoma tissue samples. MiRNA isolation from tissue samples were performed using Trizol reagent ( Sigma, USA). RNA quality and quantity were assessed using a BioMate TM 3 Series Spectrophotometers (Thermo, Madison, WI). Synthesis of cDNA with reverse transcriptase was performed by TaqManTM microRNA Reversed Transcription Kits, For analysis of miRNA expression, real-time q-PCR analyses were using TaqMan MicroRNA Assays. All real-time q-RT-PCR were performed on a 7300 real-Time PCR system (Applied Biosystems, USA). MiR-24 was used as the internal control for normalization. The relative miRNA expression levels were calculated using the 2 DΔCt methods. Values were presented as means ± standard deviation (SD). The comparison of miRNA levels in breast cancer and melanoma tissues were performed using Student’s t-test. A p value less than 0.05 was considered statistically significant. The expression of miRNAs in different breast cancer subtypes (infiltrating and Invasive ductal cancer) and melanoma (primary and metastatic) was also performed. Results: Relative miRNA expression levels (miR-15b, miR-142-3p, miR-142-5p, miR-146a, miR-199a, miR-221 and miR-424) were found to be differentially expressed in breast cancer and melanoma tissues. Significantly higher relative miRNA expression levels were detected in melanoma tissues compared with breast cancer tissues in all miRNAs evaluated except for miR-424. Four miRNAs (miR-15b, miR-146a, miR-221, and miR-143-3p) had relative expressions over 1.5 compared with only 1 miRNA (miR-15b) in breast cancer tissue. DΔCt values are plotted following comparison with endogenous levels of miR-24 assessed in each sample. Conclusions: Our study demonstrated that miRNA is not only a potential biomarker, but also a valuable therapeutic target for breast cancer and melanoma. Citation Format: Yanping Zhang, Guangyong Peng, Eddy C. Hsueh. A comparative microRNA expression analysis in breast cancer and melanoma tissues [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1794.