A friend of mine has HER2-positive breast cancer. Can you tell me what this means?

Answer From Karthik Giridhar, M.D.

HER2-positive breast cancer is a breast cancer that tests positive for a protein called human epidermal growth factor receptor 2 (HER2). This protein promotes the growth of cancer cells.

In about 1 of every 5 breast cancers, the cancer cells have extra copies of the gene that makes the HER2 protein. HER2-positive breast cancers tend to be more aggressive than other types of breast cancer.

Treatments that specifically target HER2 are very effective. These treatments are so effective that the prognosis for HER2-positive breast cancer is actually quite good.

Certain standard chemotherapy drugs also can be effective in treating HER2-positive breast cancers, although these drugs don't specifically target the HER2 protein.

Experts recommend that every invasive breast cancer be tested for the presence of HER2 because the results significantly impact treatment recommendations and decisions. HER2 testing is not done routinely for ductal carcinoma in situ, except as part of a clinical trial.

Whenever breast cancer recurs or spreads, the cancer cells should be retested for HER2 as well as for hormone receptor status, as these can change from the original diagnosis.

With

Karthik Giridhar, M.D.

Dec. 07, 2022 See more Expert Answers

See also

  1. 3D mammogram
  2. Accelerated partial breast irradiation (ABPI)
  3. Axillary dissection
  4. Biopsy procedures
  5. Blood Basics
  6. Bone scan
  7. Brachytherapy
  8. BRCA gene test
  9. Breast cancer
  10. Breast Cancer
  11. Breast cancer chemoprevention
  12. Breast Cancer Education Tool
  13. Common questions about breast cancer treatment
  14. Breast cancer prevention
  15. Infographic: Breast Cancer Risk
  16. Breast cancer risk assessment
  17. Breast cancer staging
  18. Breast cancer supportive therapy and survivorship
  19. Breast cancer surgery
  20. Breast cancer types
  21. Breast cancer-related lymphedema
  22. Breast implants and cancer
  23. Evaluating breast lumps
  24. Breast lumps
  25. Breast MRI
  26. Breast self-exam for breast awareness
  27. Cancer blood tests
  28. Cancer survivorship program
  29. Chemo targets
  30. Chemotherapy
  31. Chemotherapy and hair loss: What to expect during treatment
  32. Chemotherapy and sex: Is sexual activity OK during treatment?
  33. Chemotherapy for breast cancer
  34. Chemotherapy nausea and vomiting: Prevention is best defense
  35. Chest X-rays
  36. Complete blood count (CBC)
  37. Contrast-enhanced mammography
  38. Coping with pain after breast surgery
  39. COVID-19 vaccine: Should I reschedule my mammogram?
  40. CT scan
  41. Dense breast tissue
  42. Does soy really affect breast cancer risk?
  43. Dragon Boats and Breast Cancer
  44. Genetic Testing for Breast Cancer
  45. Genetic testing for breast cancer: Psychological and social impact
  46. Hormone therapy for breast cancer
  47. Intralesional injection therapy
  48. Lumpectomy
  49. Magic mouthwash
  50. Mammogram
  51. Mammogram guidelines: What are they?
  52. Mastectomy
  53. What is breast cancer? An expert explains
  54. Minimally invasive inguinal lymphadenectomy (MILND)
  55. Modified radical mastectomy
  56. Molecular breast imaging
  57. MRI
  58. MRI-guided breast biopsy
  59. Nipple discharge
  60. Nipple-sparing mastectomy
  61. Oncoplastic breast-conserving surgery
  62. PALS (Pets Are Loving Support)
  63. Paulas story A team approach to battling breast cancer
  64. Pink Sisters
  65. Positron emission mammography (PEM)
  66. Positron emission tomography scan
  67. Precision medicine for breast cancer
  68. Prophylactic mastectomy
  69. Radiation therapy
  70. Radiation therapy for breast cancer
  71. Seeing inside the heart with MRI
  72. Sentinel node biopsy
  73. Skin-sparing mastectomy
  74. Stereotactic breast biopsy
  75. Support groups
  76. Surgical biopsy
  77. The Long Race Beating Cancer
  78. Thyroid guard: Do I need one during a mammogram?
  79. Tomosynthesis-guided breast biopsy
  80. Ultrasound
  81. Sentinel node biopsy for melanoma
  82. Mammogram for breast cancer — What to expect
  83. MRI
  84. Weight Loss After Breast Cancer
  85. X-ray