breast cancer and hormone receptor status

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When clinicians manage breast cancer they consider various prognostic factors, including hormone receptor status and HER2 status

  • hormone receptors include oestrogen receptors and progesterone receptors
  • tumours that express either oestrogen receptors or progesterone receptors are commonly referred to as being hormone receptor positive
    • estimated that 60% and 80% of all breast cancers in premenopausal and postmenopausal women respectively are hormone receptor positive.
    • people with hormone receptor- positive breast cancer generally have a better prognosis than those with hormone-receptor-negative breast cancer

  • tumours that overexpress the human epidermal growth factor receptor 2 (HER2) protein (HER2+) grow and divide more quickly, so women with HER2+ tumours generally have a worse prognosis than women with HER2 negative tumours
    • approximately 20-30% of people with metastatic breast cancer have HER2+ tumours, of which about 50% will also be hormone receptor positive

Aim of treatment in metastatic breast cancer is to palliate symptoms, prolong survival and maintain a good quality of life with minimal adverse

  • choice of treatment depends on previous therapy, hormone receptor status, HER2 status and the extent of the disease

Notes:

  • exposure to epidermal growth factor (EGF) leads to modifications in several aspects of the cellular behavior related to the development of cancer
  • the overactivation of the human epidermal growth factor receptor (HERs), a family of tyrosine kinase receptors, leads to the development of cancer
  • EGF binds to HER1 (also known as EGF receptor or ErbB1), which is the prototype of a family that includes three additional members:
    • HER2 (also known as neu or ErbB2), HER3 and HER4 (also known as ErbB3 and ErbB4, respectively)
    • the generation of HER homo- or hetero oligomers induces the activation of the intrinsic tyrosine kinase activity of the receptors
      • the subsequent phosphorylation of intracellular tyrosine residues leads to the recruitment of factors that transfer the signal from the plasma membrane to the nucleus
        • induces changes in the expression of genes that coordinately regulate proliferation, migration, adhesion, differentiation and apoptosis
    • the involvement of HER receptors, and particularly HER2, in the development of a variety of cancers, including breast tumors, has led the implementation of different therapeutic strategies
      • include monoclonal antibodies directed against the ectodomain of the receptors, such as Herceptin (also known as Trastuzumab), and small-molecule tyrosine kinase inhibitors (1)
      • Amplification of the HER2 gene (also known as ERBB2) is present in 10-20% of tumours in patients with early-stage breast cancer and is associated with aggressive cancers and an increased risk of disease recurrence
      • Trastuzumab, a humanised IgG1 monoclonal antibody that targets the extracellular domain of the HER2 protein, improves progression-free survival and overall survival when administered in combination with chemotherapy in HER2-positive metastatic breast cancer (3)
        • benefits are also seen with trastuzumab added to chemotherapy in non-metastatic breast cancer
        • adding trastuzumab to chemotherapy for early-stage, HER2-positive breast cancer reduces recurrence of, and mortality from, breast cancer by a third

Reference:

Last edited 08/2021 and last reviewed 08/2021

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