The findings by a Cardiff University team, have been published in Nature Immunology. Researchers say that the work is still in an initial stage and is yet to be tested in patients.
However, researchers say they have "enormous potential" after discovering that this method is capable of killing prostate, breast, lung and other cancers in lab tests.
Experts said that although the work was still at an early stage, it was very exciting.
The scientists were looking for "unconventional" and previously undiscovered ways the immune system naturally attacks tumours.
What they found was a T-cell inside people's blood. This is an immune cell that can scan the body to assess whether there is a threat that needs to be eliminated.
T-cells have "receptors" on their surface that allow them to "see" at a chemical level.
The Cardiff team discovered a T-cell and its receptor that could find and kill a wide range of cancerous cells in the lab including lung, skin, blood, colon, breast, bone, prostate, ovarian, kidney and cervical cancer cells.
Crucially, it left normal tissues untouched.
(Excerpts : BBC News)