For about half a century, William B. Coley injected streptococcal organisms into thousands of his patients who had inoperable late-stage cancer at Memorial Hospital in New York City.
In most cases it worked. The procedure shrank their tumors and one patient lived 26 more years before dying of a heart attack. Unfortunately, several other patients died of bacterial infection.
Since then, there has been ongoing research into bacterial therapies for cancer. Researchers however, have found a new use for bacteria, to detect cancer rather than treat it.
The study was published in the journal of Science Translational Medicine in May. The report explains how they genetically alter a strain of E.coli bacteria so that when it encounters tumors in the liver, it releases a luminescent enzyme which shows up in urine samples.
Researchers specifically programmed the probiotics to make a molecule that would change the color of a patient’s urine to indicate the presence of cancer.
Researchers engineered Nissle 1917, the same probiotic that is often in yogurt to keep the digestive tract moving, to produce a naturally occurring enzyme called lacZ when there are tumors present in the liver.
Lab mice were injected with a molecule made of galactose and luciferin, the luminescent protein that fireflies produce. Luciferin doesn’t glow when it’s bound to the sugar, but when there is cancer present; the lacZ encounters the molecules and splits the galactose from the luciferin. The luciferin then glows and exits the body in urine.
Other cancer diagnostics have also used urine tests, especially with bladder and prostate cancer. These methods are not widespread because they can have low sensitivity, they miss some cancers.
Researchers are working on understanding the trafficking of these probiotics from the intestines into the liver and determining what other types of cancers can be used with this approach.
