Free Fatty Acids Could Help Diagnose Thyroid Cancer

January 15, 2016
Greg Kennelty

The presence or absence of certain serum-free fatty acids could be an excellent diagnostic tool to differentiate between patients with either benign thyroid diseases or thyroid cancer.

Ya-Ping Zhang

The presence or absence of certain serum-free fatty acids (FFA) could be an excellent diagnostic tool to differentiate between patients with either benign thyroid diseases (BTD) or thyroid cancer.

According to the study,1published in theJournal of Cancer, researchers from the Chinese Academy of Sciences, Peking Union Medical College, Jilin University, and Heze Municipal Hospital utilized 664 serum samples from the same number of patients to determine whether or not certain FFAs could be used to diagnose thyroid cancer. Of the 664 patient samples examined in the study, 322 were disease free, 129 samples indicated BTD, and 213 samples tested positive for thyroid cancer.

The 322 healthy control samples were recruited from China-Japan Union Hospital (n = 150) in Changchun, China, and Heze Municipal Hospital (n = 172) in Heze, China. The 213 patients with thyroid cancer were recruited from China-Japan Union Hospital (n = 88) and from Peking Union Medical College Hospital (n = 129) in Beijing, China, and the 129 patients with BTD were recruited from Peking Union Medical College Hospital.

All serum samples used were the remaining sera post-clinical lab examination and were collected the morning after overnight fasting (approximately 12 hours).

According to the study, current medical evidence indicates essential fatty acids can alter interactions between receptors and hormones. These alterations can change expressions of receptors on the cells, and previous studies done by the same group of researchers yielded results showing significant decreased unsaturated FFAs, such as C16:1, C18:1, C18:2, C18:3, C20:4, and C22:6, are closely related to the development of pancreatic cancer, lung cancer, and breast cancer.

"This study has shown a comprehensive comparison of serum FFAs between healthy controls, BTD patients, and thyroid cancer patients based on a large serum sample size," said Ya-Ping Zhang, vice president of Chinese Academy of Sciences, et al, in the study.

"Significantly decreased C16:1, C18:1, C18:2, C18:3, C20:4, and C22:6in BTD patients and thyroid cancer patients were observed compared with healthy controls, and significantly increased C16:1, C18:2, C20:4, and C22:6in TC patients were detected compared with BTD patients. Our findings indicate that lipogenesis of C16:1, C18:2, C20:4, and C22:6may involve in different metabolic pathways between BTD patients and thyroid cancer patients."

Serum samples were classified into a training set and a validation set, with healthy controls age- and sex-matched to patients with thyroid cancer in both sets. The training set consisted of 88 patients with thyroid cancer and 150 healthy patients, while the validation set consisted of 129 patients with BTD, 125 patients with thyroid cancer patients, and 172 healthy patients. Healthy controls were age- and sex-matched to thyroid cancer patients in the training and validation sets.

In the training set, data showed significant decreased C16:1, C18:1, C18:2, C18:3, C20:4, and C22:6FFAs in patients with thyroid cancer relative to their healthy counterparts. Changing trends in polyunsaturated fatty acid (PUFA) levels were also consistent with previous levels shown in the urine of patients with thyroid cancer. Data from the training set showed a combination of C16:1, C18:1, C18:2, C18:3, C20:4, and C22:6has "high diagnostic performance," able to differentiate patients with thyroid cancer from healthy patients at a sensitivity of 73.9% and a specificity of 86.0%

In the validation set, data also showed differentiation between patients with thyroid cancer patients and healthy patients with a panel of C16:1, C18:1, C18:2, C18:3, C20:4, and C22:6, at a sensitivity of 81.6%, and a specificity of 80.8%. Levels of C16:1, C18:1, C18:2, C18:3, C20:4, and C22:6in patients with BTD compared with healthy patients were "remarkably decreased," with C20:4, C22:6PUFAs as specific biomarkers to differentiate the groups at sensitivities of >83%, and the specificities of >86%.

The study also states that with C16:1, C18:2, C20:4, and C22:6,there were significant differences between patients with BTD and patients with thyroid cancer, with data indicating lipogenesis of C16:1, C18:2, C20:4, and C22:6could involve different metabolic pathways between the two groups.

A panel of C16:1, C18:2, C20:4, and C22:6was able to distinguish between patients with BTD and patients with thyroid cancer, with a sensitivity of 76.8% and a specificity of 83.7%.

Current methods of differentiating between BTD and thyroid cancer includes ultrasonography-guided fine-needle aspiration biopsy and diffusion-weighted MR imaging. The study states that the former has a better chance of diagnosing small nodules and nonpalpable thyroid nodules, while the latter lacks standard b-values.

With the potential to diagnose patients via an FFA sample, researchers hope to be able to provide medical professionals with a noninvasive method of diagnosis.

References

  1. Zhang Y, Qiu L, He C, liu Y. Serum unsaturated free fatty acids: a potential biomarker panel for differentiating benign thyroid diseases from thyroid cancer.National Center for Biotechnical Information. 2016. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4643084/. Accessed January 15, 2016.