Herbal Remedy May Contain Carcinogen

In a report that pinpoints the striking genetic alterations caused by an herbal compound, investigators had uncovered a direct link between aristolochic acid – used in a traditional herbal remedy – and upper urinary tract cancers.The researchers claim their results also demonstrate the power of genome-wide sequencing, the technique they used to determine the compound’s mutation signature, to identify individual exposure to carcinogens.

Published in the journal Science Translational Medicine, researchers focused their research on aristolochic acid. This compound is found in a group of vine plants more commonly known as birthwort. The plant has been utilized for centuries in traditional Chinese medicine and was also used by the Greeks and Egyptians before that. Their medicinal uses included easing childbirth, treating arthritis, and other conditions.

The US Food and Drug Administration has called for dietary supplements and other products containing aristolochic acid to be discontinued in 2001, when they first gave warnings of the compounds carcinogenic potential. Since then, a number of countries have banned it, and the International Agency for Research on Cancer has classified the birthwort herbal compounds as Group 1 carcinogens, indicating there is evidence they cause cancer in humans. However, a number of herbal remedies containing the substance can still be purchased online.

For the study, investigators from the US and Taiwan utilized a particular genome-wide method known as whole-exome sequencing on tumor tissue retrieved from 19 patients with upper urinary tract cancer who had been exposed to aristolochic acid, and seven patients who had no suspected exposure to the compound.

The researchers discovered an average of 753 mutations in each tumor from the exposed patients, when compared to 91 in tumors from patients who had not been exposed to aristolochic acid. This high level of mutation exceeds that found in melanoma due to ultraviolet radiation exposure and in lung cancer caused by smoking.

Co-author Kenneth Kinzler, concludes, “The technology gives us the recognizable mutational signature to say with certainty that a specific toxin is responsible for causing a specific cancer. Our hope is that using the more targeted whole-exome-sequencing process will provide the necessary data to guide public health decisions related to cancer prevention.”