...- Patients must be diagnosed with metastatic cytologically or histologically confirmed adenocarcinoma of the breast with HER2 over-expression or with newly diagnosed locally advanced (including inflammatory) breast cancer (LABC) with stage II-III disease; patients with metastatic (stage IV) disease (MBC) must have measurable lesions...

...Patients ≥ 18 years of age with histologically, and radiographically confirmed non-metastatic ER-positive (defined as ≥30% of positive cells) and HER2-positive (defined as overexpression by immunohistochemistry (3+) or 2+ and positive by defined by fluorescence or dual in situ hybridization.) breast cancer with minimal tumor size over 2 cm (≥T2 lesion) to receive neoadjuvant chemotherapy recommended by the treating physician 2....

...HER2 overexpression or amplification will be based on local test results and is defined as either: (i) IHC staining of 3+ (uniform, intense membrane staining) in greater than or equal to 10% of invasive tumor cells or, (ii) Fluorescent in situ hybridization (FISH) result of more than six HER2 gene copies per nucleus or, (iii) FISH ratio (HER2 gene signals to chromosome 17 signals) of greater than or equal to 2.0....

...Patients > 18 years of age with HER2-overexpressing early stage breast cancer (Stages I...

...- Overexpression and/or amplification of HER2 in an invasive component of the core biopsy, according to one of the following definitions: •>30% of invasive tumor cells showing strong complete circumferential membrane staining (score 3+) •HER2 gene amplification defined as >6 HER2 gene copies per nucleus by in situ hybridization....

For patients with HER2+ breast cancer who undergo NAT, the degree of HER2 protein overexpression and gene amplification were associated with response to NAT.

HER2-positive MBC received 0 or 1 prior therapy received intravenous paclitaxel (80 mg/m2 weekly) with trastuzumab (8 mg/kg loading dose followed by 6 mg/kg every 3 weeks) and pertuzumab (840 mg loading dose followed by 420 mg every 3 weeks),...The median PFS was 24.2 months (95 % CI 17-35) for overall population; it was 25.7 months (95 % CI 17.0-NR) and 20.1 months (95 % CI 8.5-33.0) for patients with 0 and 1 prior treatment, respectively...With a longer follow-up of almost 5 years, combination of weekly paclitaxel, trastuzumab, and pertuzumab remains effective with a favorable median PFS...

 The results suggest that the TRAS + PER combination may be effective in T-DM1-resistant cancer cells where HER2 overexpression is maintained.