Luminal B Breast Cancer

Luminal B breast cancer is a subtype of breast cancer that is determined by the genetic makeup of cancer cells. It is one of five current groups of breast cancer categorized by the molecular patterns and behaviors of cancer cells.

This type of breast cancer looks like cancers that begin in the inner luminal cells that line the mammary ducts.

Causes of Luminal B Breast Cancer

As with all types of breast cancer, what exactly causes the luminal B subtype of cancer is unknown. In general, there are a variety of risk factors to consider, including:

  • Being older than 50
  • Having a family history of breast or ovarian cancer
  • Inheriting genetic mutations
  • Being overweight or obese
  • Drinking alcohol
  • Having dense breast tissue
  • Having had breast cancer or non-cancerous breast diseases previously
  • Undergoing radiation treatments to the chest
  • Bearing children after the age of 30
  • Never bearing children

Symptoms of Luminal B Breast Cancer

The hallmark characteristic of most breast cancers is a hard or rubbery lump in the breast. The lump may feel like it is fixed into the breast tissue and can’t be moved.

Other breast cancer symptoms include:

  • Abnormal pain in one or both breasts
  • Changes in how one or both nipples look
  • Reddening, dimpling, swelling or thickening of breast skin
  • Nipple discharge that is not breastmilk

Diagnosis of Luminal B Breast Cancer

Similar to the diagnostic process for other types of breast cancer, a biopsy is performed to obtain a sample of breast tissue. From there, pathology reports and imaging tests are reviewed.

Other diagnostic reviews include:

  • Seeing how the cells look under a microscope – Cells with unique appearances and shapes are identified, as well as the differences between cancer cells and normal cells.
  • Determining the type of hormone receptor the breast cancer cells have – It is determined whether cells have estrogen or progesterone receptors, which can be grouped under hormone receptor (HR) negative and positive designations.

The goal of diagnosing any type of breast cancer is ultimately to determine the genetic makeup of the breast cancer cells.

Luminal B malignancies feature cells that are:

  • HR-positive
  • HER2-positive
  • High in levels of Ki-67 protein, which helps to control cancer cell growth speed

Luminal B cells are considered a more aggressive form of cancer compared to luminal A cells and have a somewhat worse prognosis.

Treatments for Luminal B Breast Cancer

At Tampa General Hospital Cancer Institute, treating patients with luminal B cancer begins with our multidisciplinary experts who work together to create a highly personalized treatment plan. For instance, this type of breast cancer may respond best to:

  • Chemotherapy
  • Hormone therapy
  • Treatments that target the HER2 growth-promoting protein