Indicators of L-arginine metabolism in saliva: A focus on breast cancer

Objectives: To analyze the arginase activity, the level of nitric oxide (NO) and the cytokine profile of saliva in patients with breast cancer. Methods: A total of 114 volunteers took part in this caseecontrol study, and were divided into three groups as follows: The main group (breast cancer, n = 43), the comparison group (fibroadenomas, n = 32), and the control group (conditionally healthy, n = 39). All participants underwent biochemical examination of saliva and histological verification of the diagnosis. Results: We found that the arginase activity in the saliva of breast cancer patients was significantly higher, and the level of NO was lower than in the control group. The 'arginase:NO' ratio was 0.22 for the control group, 0.98 for the comparison group (p = 0.0040), and 1.48 for the breast cancer group (p < 0.0001). The maximum increase in the `arginase:NO' is characteristic of the early stages of the disease, which makes this ratio potentially applicable for the diagnosis of breast cancer with sensitivity and specificity of 81.1% and 81.0%, respectively. It was not possible to establish an unambiguous relationship between the level of cytokines and the metabolic parameters of L-arginine. However, we found an increase in salivary cytokine levels in breast cancer, and thus may represent an independent direction of research. Conclusions: Saliva can be used as a substrate to determine L-arginine metabolic parameters. (C) 2021 Japanese Association for Oral Biology. Published by Elsevier B.V. All rights reserved.

Automated summary

Patients with breast cancer exhibited significantly higher arginase activity and lower nitric oxide levels in saliva compared to controls. The 'arginase:NO' ratio was found to be highest in the breast cancer group at 1.48, suggesting potential diagnostic value for breast cancer in early stages. An increase in salivary cytokine levels in breast cancer patients may also warrant further independent research.