Long non-coding RNAs may be additional markers in the diagnosis of thyroid cancer
In recent years, more and more new long noncoding RNAs have been discovered; they do not participate in the process of protein synthesis. Accordingly, the question arises as to what functions they perform in the human body. We know already that long noncoding RNAs primarily regulate the work of their target genes. When the concentration of long noncoding RNAs changes, the level of expression of individual genes also changes. This may include suppressor genes, i.e., genes that suppress tumor genesis, or vice versa, genes whose expression triggers carcinogenesis, i.e., tumor growth.
It has been found out which of the recently discovered long non-coding RNAs are involved in the development of breast cancer and lung cancer. Specialists at the RCMG Epigenetics laboratory discovered that these RNAs also played an important role in the development of thyroid cancer.
Valentina Yakushina, senior researcher at the RCMG Epigenetics Laboratory, "In addition to providing further evidence for involvement of some long noncoding RNAs in tumor transformation of thyroid cells, we have seen the association of recently discovered long noncoding RNAs with different thyroid cancer subtypes."
Diagnosis of neoplasms of the thyroid gland can be very challenging; the main challenge is the difference between a benign neoplasm, an adenoma, and a malignant one, a carcinoma. Today, in 60% of cases after surgery on removing a thyroid gland fragment, the tumor turns out to be benign.
The cancer diagnosis is made based on the results of several tests, the main one being a biopsy, i.e. taking a sample of neoplasm tissue.
Vladimir Strelnikov, Dr.Biol.Sc., Head of the RCMG Epigenetics Laboratory, “Fine-needle biopsy allows us to take a very small amount of material, which means that it is difficult to perform several tests. In some cases, the material is insufficient to accurately determine the type of tumor. Therefore, new methods that allow us to classify the neoplasm prior to surgery are now in high demand.”
Experts at the RCMG Epigenetics Laboratory put forward the theory that the number of certain long noncoding RNAs in each specific case can tell whether the tumor is malignant or benign, as well as show a specific subtype of malignant neoplasm. During work supported by a grant from the Russian Science Foundation, the researchers showed that analysis of long non-coding RNAs will not distinguish between benign adenoma and malignant follicular carcinoma, even at the molecular level; these tumors are similar at the level of gene expression regulation. However, it has been established that different types of thyroid cancer have their own set of long non-coding RNAs. In oncology, tumor differentiation and subtype identification are of key importance for the choice of treatment tactics.
Several types of thyroid cancer are distinguished today:
- Papillary carcinoma. This is the most frequent malignant neoplasm.
- Follicular carcinoma. These tumors, as a rule, are characterized by slow growth.
- Anaplastic carcinoma. This is the most aggressive type of thyroid cancer.
Valentina Yakushina, senior researcher at the RCMG Epigenetics Laboratory, “Cells of each type of thyroid cancer turned out to carry their own, specific only for them, set of long noncoding RNAs. These RNAs can relate to the clinical course of the disease and metastasis patterns. This information can be important for doctors in the future, as it will help them choose the most effective treatment approach. Today, however, our work remains fundamental; it broadens the scope of knowledge about the role of long noncoding RNAs in the body. We cannot expect our results to be used in clinical practice anytime soon. However, we can expect that over time, with the accumulation of sufficient data, confirming the effectiveness and the informative value of the method in clinical practice, the analysis of long noncoding RNAs will complement existing methods, for example, histochemical study".
The study of long noncoding RNAs is a global trend in oncogenetics. However, today there are almost no studies devoted to their role in the development of thyroid cancer. The Epigenetics laboratory of the Academician N.P. Bochkov Research Centre for Medical Genetics was one of the first in the world to start studying this subject and obtained significant results.
Yakushina VD, Strelnikov VV, Tanas AS, Lavrov AV. Long noncoding RNA landscapes specific to benign and malignant thyroid neoplasms of distinct histological subtypes. Sci Rep. 2021 Aug 18;11(1):16728. doi: 10.1038/s41598-021-96149-2. PMID: 34408227; PMCID: PMC8373968.