Can we use an antibody to strengthen patients’ own immune system to fight childhood soft tissue cancer?

Teachable moment in classrooms:

1. tissue chapter – general characteristics of epithelial and connective tissues
2. cellular basis of life chapter – proteins in cell membranes can serve as receptors
3. immune system chapter – CD8-T-cells actively destroy target cells
4. immune system chapter – antibodies can be engineered to bind to specific targets

The news item:

Recently a newly approved treatment for childhood soft tissue cancer was reported:

Drug Approved to Help Young Patients Battle a Rare Cancer

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The article states that the drug Tecentriq was approved for use against alveolar soft part sarcoma (a soft tissue cancer). About 80 children and adults in the USA are diagnosed each year with his sarcoma, and most conventional treatments fail to fight it. The article also states that Tecentriq is an anti-PD-L1 inhibitor, and works by helping the immune system respond more strongly to cancer.

So, Why Do I Care??  While the overall number of cancer patients diagnosed with alveolar soft part sarcoma is low, these patients could not be helped by regular cancer treatments. Finding new cancer treatment approaches for these patients opens the possibility to treat other cancers where traditional cancer treatment failed.

Plain English, Please!!!  First, let’s talk about what a sarcoma is. The sarcoma type of cancers start from connective tissue, as opposed to the carcinoma type of cancers that start from epithelial tissues. The general course of the sarcomas is similar to other cancers, and that includes local growth, and the spreading, metastasizing throughout the body. Alveolar soft part sarcoma was named such, because the cancer cells form baggy, alveolus-looking microscopic structures.

Second, let’s talk about how cancer cells can slow down the immune system. One normal function of our immune system is to detect and destroy cells that show evidence of infection or abnormal components. Cancer cells have abnormal components, and our immune system, through the action of white blood cells, such as CD8-T-cells, eliminate many cancer cells. One way cancer cells can avoid destruction is by telling the T-cells to slow down. The T-cells have a “slow down” button on their surface, the PD receptor molecule. Once a molecular finger, a PD ligand or PD-L, pushes that button, the T-cells will slow their destructive activity.  Alveolar soft part sarcoma cells make PD-L molecules, and when the CD8-T-cells the attack the sarcoma cells, the PD-L on the sarcoma cells push the “slow down” button of the T-cells to slow down their attack.

Third, let’s talk about how Tecentriq strengthens immune response does our immune system destroys cancer cells. The pharmaceutical agent Tecentriq is an antibody that was engineered to stick to the PD-L finger on the sarcoma cells. Imagine that you are texting on your phone, and then a piece of french fries gets stuck to your finger. You could no longer text with that finger, because you couldn’t precisely touch the screen. Tecentriq is a molecule that, like a piece of fries, sticks to the PD-L molecule of the sarcoma cells. The sarcoma cells can no longer slow down the T-cells, so the immune system of the patient can now destroy the sarcoma.