What would happen if a few cancer cells from another person were injected into your bloodstream?

Something like this has already been done in a horribly unethical experiment. In the 1950s, a virologist and cancer researcher at Sloan Kettering named Chester Southam was working with the famous HeLa strain of cancer cells (named for the source patient Henrietta Lacks). He wanted to know if there was a danger of these giving cancer to one of the researchers by accidental exposure.

In 1954, he injected HeLa cells into a dozen hospitalized cancer patients without telling them what he was doing or why. He lied and said he was testing their immune systems, but he was really experimenting to see if the cancer from Henrietta Lacks would grow in another person. Several of these grew to tumors about 2 cm in size and one metastasized to the patient’s lymph nodes.

Since these patients already had other cancers, Southam next wanted to see if the HeLa tumors would take in healthy persons. One hundred fifty state prisoners volunteered for various reasons (such as feeling it would help atone for their crimes) and he injected HeLa into 65 of them in 1956. Tumors grew in the prisoners too, on the arms at the injection site. All of the prisoners’ bodies fought them off and the tumors vanished.

Southam injected HeLa into more than 600 other people in the years following that, incuding every OB-GYN surgery patient at Sloan Kettering, lying to these patients about what he was doing. “We’re just testing for cancer,” he told them.

When all of this came to light in the 1960s, a reporter from Science asked Southam why he didn’t inject the cells into himself. His reply was basically that he was more important than these patients; his life less dispensable. “Let’s face it,” he said to the reporter, “there are relatively few skilled cancer researchers, and it seemed stupid to take even a little risk.”

Stupid to risk his life for research; not too stupid (in his opinion) to risk the lives of hundreds of other people.

The ethical codes in place today would prohibit such a horrific experiment. Southam’s career would have been at an end if he had done such experiments in disregard to any such code of medical ethics, and he likely would have been stripped of his medical license and perhaps imprisoned. But such codes didn’t exist in the 1950s.