Genomic Alterations of Tumors in HER2-Low Breast Cancers

Yi Fang Tsai, Chi Cheng Huang, Chih Yi Hsu, Chin Jung Feng, Yen Shu Lin, Ta Chung Chao, Jiun I. Lai, Pei Ju Lien, Chun Yu Liu, Jen Hwey Chiu*, Ling Ming Tseng

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The aim of this study was to elucidate molecular profiling in HER2-low tumors based on a promising dataset. A total of 615 consecutive HER2-negative breast cancer samples were assayed. The genomic mutations in the two groups with different HER2 expression levels (HER2-0 vs. HER2-low) were compared. The mutation types obtained via next-generation targeted sequencing were correlated with the clinicopathological features of the patients with HER2-0 and HER2-low breast cancer. The results showed that there was a significantly higher percentage of receptor-positive (ER/PR) tumors and more low-level Ki-67 tumors, but a lower incidence of stage I/II tumors in the HER2-low group compared to the HER2-0 group. There was a significantly higher frequency of 17.62% (65/369) for PIK3CA_SNA in the HER2-low group than in the HER2-0 group, which had a frequency of only 9.35% (23/246) (p = 0.006). When the called gene alterations in the triple-negative breast cancer (TNBC) group were compared with those in the luminal-like breast cancer group, there was a significantly high frequency of 28.17% (140/497) for ERBB2_SNA in a luminal-like group than in the TNBC group(16.95% (20/118)).We conclude that the early detection of PIK3CA mutations is likely to be important and might help therapeutic decision making in patients with HER2-low tumors.

Original languageEnglish
Article number1318
JournalInternational Journal Of Molecular Sciences
Issue number2
StatePublished - Jan 2024


  • HER2-low carcinoma
  • breast cancer
  • human epidermal growth factor receptor-2
  • next-generation sequencing


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