One way to classify breast cancer is by identifying the genes or receptors present on the surface of cancer cells. Luminal B breast cancer is a specific subtype characterized by the presence of hormone receptors and/or the HER2 protein.
Typically, a breast biopsy is performed to determine the subtype of cancer you have. Knowing the exact type of cancer helps doctors develop the most appropriate treatment plan for you.
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What is Luminal B Breast Cancer?
Luminal B breast cancer is a subtype of breast cancer. There are several types of breast cancer, classified based on the presence of specific receptors or genes, or by their level of aggressiveness.
Luminal B breast cancer means that the cancer cells have:
- Positive hormone receptors (HR+), including estrogen receptor-positive (ER+), progesterone receptor-positive (PR+), or both.
- Human epidermal growth factor receptor 2 (HER2) positive status.
- High levels of Ki-67 protein.
The presence of HER2 protein or Ki-67 in cancer cells indicates that the breast tumor is actively growing.
Apart from Luminal B, there is also Luminal A breast cancer. The key difference is that Luminal A breast cancer has HR-positive status but is HER2-negative.
Compared to Luminal A, Luminal B breast cancer is often detected at a later stage. However, this type of cancer often responds well to targeted HER2 therapy.
Other subtypes of breast cancer besides Luminal B include:
- Luminal A (HR+/HER2-)
- Triple-negative (HR-/HER2-)
- HER2-enriched (HR-/HER2+)
Luminal B breast cancer is less common than Luminal A, accounting for only about 10% of all breast cancer cases.
Symptoms of Luminal B Breast Cancer
The symptoms of Luminal B breast cancer are similar to those of other breast cancers, including:
- A lump in the breast or underarm.
- Changes in breast shape.
- One breast appearing larger than the other.
- Breast skin resembling an orange peel texture.
- Inverted nipple.
- Unusual nipple discharge.
- Breast pain.
To detect symptoms early, perform breast self-examinations (BSE) regularly every month as part of breast cancer prevention.
Diagnosis of Luminal B Breast Cancer
The initial diagnosis of Luminal B breast cancer is similar to other breast cancer screenings. If you experience early symptoms and seek medical advice, doctors may perform several tests.
Initially, a mammogram or breast MRI may be performed. If a suspicious breast tumor is detected, a breast biopsy will be recommended to check for malignancy.
The biopsy sample is sent to a laboratory for further testing, including immunohistochemistry (IHC). This test identifies which receptors are present in the cancer cells and helps doctors determine which receptors are “feeding” the cancer cells.
Immunohistochemistry can provide information about:
- Hormone receptor status (HR) – whether cancer cells are sensitive to estrogen or progesterone.
- HER2 status – whether the cancer is HER2-positive or negative.
- Ki-67 levels – Ki-67 is a protein that indicates how rapidly cancer cells are dividing and growing. Higher Ki-67 levels suggest a more aggressive cancer.
Based on these results, doctors can determine the most appropriate treatment.
Treatment for Luminal B Breast Cancer
Breast cancer treatment depends on several factors, including:
- Age and overall health condition.
- The stage of breast cancer at diagnosis.
- HER2 status.
- Whether there are genetic mutations.
- Whether the patient has undergone menopause.
Luminal B breast cancer often responds well to hormone therapy or targeted therapy with drugs that specifically target HER2 receptors, such as trastuzumab, pertuzumab, tucatinib, neratinib, and ribociclib.
Hormone therapy for breast cancer is typically administered as oral medication, such as tamoxifen, LHRH agonists, and fulvestrant.
In addition, doctors may recommend a combination of breast cancer treatments, including:
- Radiation therapy
- Breast cancer surgery
- Chemotherapy
Prognosis for Luminal B Breast Cancer
Luminal B breast cancer tends to be slightly more aggressive than Luminal A. However, the prognosis remains favorable. According to the National Cancer Institute, the five-year survival rate for HER2-positive or HR+ breast cancer is approximately 90.7%.
Survival rates depend on several factors, including the body’s response to treatment, overall health, and age. Consult a doctor to discuss the most suitable treatment options for your condition.
You can visit the Breast Advance Cancer Center (BRAVE) at Mandaya Royal Hospital to consult with experienced medical oncology specialists. Doctors can perform a series of examinations to determine the best treatment for you.
Book an appointment via WhatsApp Chat, the Book Appointment page, or the Care Doctor app, available on Google Play and the App Store. You can also check queue numbers for a more convenient consultation experience with a doctor.
