Liver cancer can be recognized by RNA fragments in saliva and blood

Reviewed by Emily Henderson, B.Sc.Nov 23 2021

RUDN University doctors examined markers of liver cancer and found that the disease can be recognized by RNA fragments in saliva and blood. The results are published in Oncotarget.

Liver cancer is less common than other cancers, but it has lower survival rates. Sometimes it appears suddenly, but in most cases, it is preceded by other liver diseases. For example, liver cirrhosis due to hepatitis C. However, in this case, the development of liver cancer can occur imperceptibly. It is difficult to diagnose it in the early stages. That's why it is important to develop ways to find liver cancer in people at risk before it is too late.

Despite the relatively rare malignancy of liver cirrhosis, including those associated with the hepatitis C virus, and the coming era of direct antiviral drugs, there is a pool of patients with cirrhosis who are at risk of developing liver cancer. Of course, in these cases, cancer is not that unexpected disease, but it can be clinically invisible for a long time. So, methods for detecting molecular changes in the early stages are important."

Alisa Petkevich, researcher at the Department of Hospital Therapy with a course of endocrinology, hematology and clinical laboratory diagnostics of RUDN University

RUDN University doctors have found that microRNA (small sequences of RNA that do not encode genes but are involved in the regulation of their expression) can be a marker of liver cancer. Doctors took blood and saliva samples from 29 patients with cirrhosis, 24 patients with liver cancer and 21 healthy volunteers and compared the expression level of 10 different microRNAs in the samples.

Seven microRNAs that were found in the blood plasma outside the exosomes (the vesicles secreted by cells) were associated with liver cancer. Three of them were also found in saliva. This can be important for diagnosis, since saliva analysis is significantly simpler as the collection of the sample does not need a professional, the patients can do it themselves. The microRNAs found inside the exosomes may become even more effective marker of liver cancer. For them, saliva is even preferable for analysis than blood. Therefore, depending on what biological material is available, it is possible to estimate the development of liver cancer by exosomal and non-exosomal microRNAs.

"The incidence rate, along with other factors, including the reluctance of at-risk patients to systematically come to the research center for blood sampling, complicates the collection of samples to identify markers for early diagnosis. A possible solution could be the use of biomaterial that does not require medical personnel for its collection, such as saliva. We proved that saliva is a promising source of exosomal and non-exosomal microRNAs. Exosomal microRNAs have shown a strong association with primary liver cancer in saliva samples," said Alisa Petkevich, researcher at the Department of Hospital Therapy with a course of endocrinology, hematology and clinical laboratory diagnostics of RUDN University.