Aims: 1) Describe the trend in new incidence of breast cancer (BC) in the world and in Vietnam and 2) Describe the trend in diagnosis of HER2 in BC patients. Materials and Methods: A number of studies and reports on the trend of cancer incidence of BC and diagnosis of HER2 in the period 2010-2022 in the world and in Vietnam. Synthesize and analyze data collected from 20 studies and articles on major online medical databases inclusive Medline/Pubmed, Web of Science, CI5 and GLOBOCAN; Domestic Medical Journal; Documents, Research Works, Thesis, Data Reported at International and Domestic Meeting. Zotero 6.0 software was used to manage and cite collected documents. Results: 20 studies and reports in the world and in Vietnam were selected for the study, including seven documents on new trends of BC by time and geography, 13 documents on new trends for diagnosis of HER2. The incidence of BC tends to increase in the world and in Vietnam. Vietnam has a lower incidence rate than the world, but has a high mortality rate from cancer (10.5 deaths/26.4 new cases/100,000 population) equivalent to nearly 40%, common aged 50-59. Immunohistochemistry (IHC) is chosen as the routine test in the diagnosis of BC and FISH is the gold standard for evaluating HER2 gene amplification with a sensitivity of up to 98% with a specificity of 100%. Conclusion: Vietnam is in the trend of increasing the incidence of BC in the world, mainly in the age group 50-59 during menopause, the mortality rate due to cancer is high, accounting for about 40% of all cases. new. The diagnosis of HER2 in BC is confirmed, the first test is IHC, FISH/CISH techniques.

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