Enhanced CAR-T therapy clears solid tumours by finding ‘faint’ targets

Chimeric antigen receptor (CAR) T-cell therapy, an approach that modifies a patient’s own immune cells to hunt down cancer, has transformed treatment for blood cancers such as leukaemia and lymphoma. But the same strategy has struggled when applied to solid tumours such as kidney or ovarian cancer.

One of the biggest obstacles is antigen heterogeneity. Tumours are not made of identical cells. Instead, they resemble a patchwork: some cells display the protein that CAR-T cells detect while others appear to lack it. CAR-T cells only destroy ‘visible’ targets, so the invisible cells survive and allow the cancer to grow back.

Now, a study published in Science on February 26 has suggested these supposedly invisible cells may not be invisible after all. Many tumour cells thought to lack the target protein actually carry small amounts — too little for current CAR-T cells to detect.