Laboratory of Translational Oncology works to fight cancers of unknown primary

A paper was published in Critical Reviews in Oncology/Hematology.

"When diagnosing cancer, in 95 percent of patients, the tumor is detected in the organs in which it began its development. This principle determines the treatment regimen. So, for example, the drugs for treating kidney cancer and prostate cancer will be different. However, in 5 percent of patients, the primary focus can be so small that the disease can be detected only at the time of development of metastases, which in itself is an unfavorable fact for the patient and an extremely difficult task for oncologists. This group of tumors is called tumors of unknown primary," shares Junior Research Associate Mariya Zolotykh.

Such patients can be classified into two groups.

"In the first group of patients (it makes up 20 percent of the total), CUP is treatable. This group, for example, includes those who have single metastases of squamous cell carcinoma in the inguinal or cervical lymph nodes. The second group (80 percent) are patients with a poor prognosis, of whom only half will survive 6 months after diagnosis," continues the scientist.

Molecular diagnostics and individual approaches pave new ways for CUP treatment. The main objective here is to detect the origins of cancer cells and their way of attacking an organ to beget a secondary tumor.

"Back in 1889, Stephen Paget proposed a theory of metastasis called seed and soil. Its essence is the following: the growth of metastases (the "seed" in this case is a single tumor cell circulating in the bloodstream) requires a suitable environment in the surrounding tissues (the "soil"). In simple terms, a secondary tumor develops in those tissues in which the surrounding conditions are initially favorable for its growth. We assume that by determining where metastases have formed, we can figure out where the primary tumor may have formed," explains Lad Head Regina Miftakhova.

The Laboratory studies metastases in various cancers to decipher the riddles of CUP.

"At the first stage, we conducted an analytical study, thanks to which we were able to collect statistical data on the most common areas of metastasis of tumors of known primary localization, the localization of metastatic foci in CUP and the frequency of detection of primary foci for each of them. For example, it was found that neoplasms in CUP are most often found in the liver, lungs and pleura, central nervous system, peritoneum and lymph nodes. In this case, the culprit for the development of metastases in the brain, liver and bones is lung cancer, and if CUP is detected in the lung, prostate and thyroid cancer is the culprit. In some cases, this coincides with the pattern of spread of metastases in cancers in which the primary tumor is already known, in others it is not. Our task is to understand what distinguishes these two processes," concludes Dr. Miftakhova.

The team plans to identify and classify cancer cells circulating in blood to determine the most aggressive phenotypes and to find new markers of metastasis. The research is conducted in cooperation with Republican Clinical Oncological Hospital and supported by the Russian Science Foundation.

More information:
Cancer of unknown primary and the "seed and soil" hypothesis
www.sciencedirect.com/science/ … ii/S1040842824000404

Provided by Kazan Federal University