Immunohistochemistry (IHC) - PD-L1 Testing (SP263 CLONE)

PDL-1 test

It is a test that is used to measure the total amount of PDL-1 on cancer (malignant) cells. The expanded form of PDL-1 is programmed death-ligand 1.PDL-1 is also called immune checkpoint inhibitor . The PDL-1 testing is also called PDL-1 IHC (Immunohistochemistry) test.

In general whenever there is any bacterial or viral infection, immune system of your body is activated to destroy these foreign organisms. In such circumstances it does not destroy other healthy cells in the body. This happens because of PDL-1 protein. PDL-1 is a type of protein that prevents the immune system of the body from destroying its own healthy cells. In certain cancers, some cancer cells may have high levels of PDL-1.This prevents the cancer cells from being destroyed by the immune system.

The purpose of PDL-1 testing is to know whether immunotherapy (a type of cancer treatment) may be beneficial in a particular cancer. If the cancer cells have high levels of PDL-1 immunotherapy can be useful for treatment. It is a type of therapy that strengthens the immune system to help identify and kill cancer cells. The advantage of this cancer therapy is that it has very less side effects as compared to other cancer treatments. The various drugs (also called PDL-1inhibitors) used in immunotherapy are atezolizumab, durvalumab, nivolumab and pembrolizumab

Why is PDL-1 test prescribed?

The healthcare provider may advise this test to know whether immunotherapy may be beneficial especially in certain cancers (where cancer cells have high PDL-1 levels) such as:

• Melanoma
• Hodgkin’s lymphoma
• Bladder cancer
• Kidney cancer
• Breast cancer
• Non-small cell lung cancer
• Cervical cancer
• Stomach cancer
• Head and neck cancer

Sometimes this test is also done when cancer spreads again after chemotherapy or any other cancer treatment.

Procedure and prerequisites

This test is done on specimen obtained by biopsy. The main types of biopsy procedure used are fine needle aspiration biopsy, core needle biopsy and surgical biopsy This tissue obtained by core biopsy or surgical biopsy procedure is formalin fixed in 10% formalin and is formed into formalin fixed and paraffin embedded block. It is vital to submit relevant clinical history along with histopathology, cytopathology and radiological report

Reference range

The result may be PDL-1 present (expressed) or absent (not expressed) in the given biopsy specimen. If result is positive then immunotherapy may be useful for that cancer. If result is negative that means immunotherapy is not very useful in that cancer.