October is Breast Cancer Awareness Month!!!
Breast cancer is one of the most common cancers worldwide, affecting both females and males. It has been estimated that in 2020 approximately 2.3 million females were diagnosed with breast cancer worldwide, accounting about 24.5% of all cancer cases. In the United States, it has been estimated that in 2022 approximately 287,850 new cases of invasive breast cancer and 51,400 in situ breast cancer were diagnosed among US women, and about 43,250 women would die from breast cancer. Early detection and timely treatment have contributed to reduce the mortality rate of breast cancer. Immunohistochemistry (IHC) detection plays a crucial role in characterizing breast cancers, helping to determine its subtypes, prognosis, and treatment options. Here are some common IHC markers used in breast cancer diagnosis:
1. Estrogen Receptor (ER): ER is a hormone receptor protein found in the nuclei of breast cancer
cells. ER-positive breast cancer cells are often responsive well to hormone therapy.
2. Progesterone Receptor (PR): PR is another hormone receptor protein, and like ER, it is found in
the nuclei of breast cancer cells. PR-positive breast cancer cells are responsive well to hormone
3. Human Epidermal Growth Factor Receptor 2 (HER2/neu): HER2/neu is a protein that promotes
breast cancer cell growth. In about 20% of breast cancer the cancer cells have extra copies of
HER2/neu gene that makes the Her2 protein. HER2-overexpressed breast cancers tend to be more
aggressive than other subtypes of breast cancer. Treatments that specifically target HER2 protein are
very effective that the prognosis for HER2-positive breast cancer is actually quite good.
4. Ki-67 (MIB-1): Ki-67 is a marker of cell proliferation. High levels of Ki-67 expression in breast
cancer cells shown by IHC indicate very aggressive breast cancer in general with high grade breast
cancer and poor prognosis.
5. Mammaglobin A: Mammaglobin detection by IHC shows high specificity in determining the breast
cancer. While physicians encounter a cancer of unknown primary, mammaglobin can be used for
identifying the origin of the cancer of unknown primary as a breast origin. This mammaglobin
marker has been often used in the differential diagnosis of cancers.
6. GCDFP-15: GCDFP-15 detection by IHC shows high specificity in determining the breast cancer.
While physicians encounter a cancer of unknown primary, GCDFP-15 can be used for identifying the
origin of the cancer of unknown primary as a breast origin. This GCDFP-15 marker has been
frequently used in the differential diagnosis of cancers.
7. CK5, CK14, and CK17: These cytokeratin markers are frequently used to identify basal-like breast
cancer, a subtype that is typically triple-negative (ER-, PR-, HER2-), which accounts for approximately
15%-20% of breast cancer and needs to develop new treatment. Early detection saves lives.