Breast Cancer
Breast cancer can be invasive or noninvasive. Invasive breast cancer spreads into surrounding tissues. Noninvasive breast cancer does not go beyond the milk ducts or lobules in the breast. Most breast cancers start in the ducts or lobes and are called ductal carcinoma or lobular carcinoma. Breast cancers can also be divided into three large subtypes based on the biomarkers they express. These are Hormone receptor-positive, Herz positive and triple negative breast cancer.
Hormone receptor-positive: Breast cancers expressing estrogen receptors (ER) and/or progesterone receptors (PR) are called “hormone receptor-positive.About 606 to 75% of breast cancers have estrogen and/or progesterone receptors.
Her2 positive: About 1_% to 20% of breast cancers depend on the gene called human epidermal growth factor receptor 2 (HER2) to grow.HER2-positive breast cancers grow more quickly. They can also be either hormone receptor-positive or hormone receptor-negative.
Triple negative: Tumor that does not express ER, PR, or HER2, the tumor is called triple-negative.Triple-negative cancer is also more common in women witha mutation in the BRCAa or BRCA2 genes. Guidelines require triple-negative breast cancer patients younger than 6oyrs to be tested for BRCA gene mutations.
Below is the list of genes that have clinical significance in management of breast cancer patients. These genes are analyzed using tests: Microsatellite instabillity (MSI), OncoCEPT-Solid.
Tests Offered
1. ER + Her2 -
ER + Her2+
Genes analyzed: PIK3CA
2. ER - PR - Her2 - (NBC)
BRCA1, BRCA2, PALBL, RAD51 & OTHER BRCAness Genes
4. PDL1
Immunotherapy companion diagnostic FDA approved Biomarkers-PDL1 (22C3 – DAKO, SP263,SP142 – Ventanna) by IHC
Our body’s immune system detects Infected cells and tumour cells and eliminated by cytotoxic T lymphocytes. Normal cells differentiate themselves by expressing a protein signal called PD-L1 to limit harm to surrounding tissue (programmed death ligand 1). This PD-L1 signal is a stop sign meant to prevent cytotoxic T cells from destroying normal cells. T cells use a receptor called PD-1 to identify the PD-L1 signal (programmed death receptor 1). Some tumours can also express the PD-L1 signal in order to deceive the immune system and avoid being detected. Anti-PD-1 therapy works by preventing the interaction between PD-1 and PD-L1 of tumour cells. Patient response from anti-PD-1 therapy (immunotherapy) is associated with PD-L1 expression. Different clones of PDL1 are validated against different targeted immunotherapies and hence specific PDL1 clone is to be requested for IHC test based on Targeted immunotherapeutic drugs for eg. PDL1 22C3 for Pembrolizumab.