MicroRNA signature for HER2-positive breast and gastric cancer.

Background/aim: The molecular mechanism for aggressive clinical behaviour related to v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 2 (ERBB2) amplification is not fully-understood. In particular, little is known about microRNAs in the human epidermal growth factor receptor 2 (HER2) signaling network.

Patients And Methods: Using microRNA microarray, the microRNA profiles of 16 HER2-positive breast carcinomas were compared with those of five luminal-type breast carcinomas. Additionally, two frozen, ERBB2-amplified gastric carcinomas were compared with their adjacent normal tissue samples. MicroRNAs that were differentially expressed according to the HER2 status in breast and gastric carcinomas were identified as the HER2 microRNA signature.

Results: MiR-337 and miR-302f were commonly overexpressed in HER2-postive breast and gastric cancer. MiR-139 and miR-129 were commonly underexpressed in HER2-positive breast and gastric cancer. A concordant pattern of microRNA expression was noted between discovery sets and the majority of candidate microRNAs (two out of three) in three validation sets.

Conclusion: Our study identified novel microRNAs that were differentially expressed according to the HER2 status across different tumor types.