br Results It has been shown that it is
Results: It has been shown that it is possible to determine changes in lipid levels in ovarian and endometrial cancer using saliva. It has been established that the ratio of the intensity of the CAY10683 bands 2923/ 2957 cm−1 is statistically significantly reduced against the background of the pathologies of the ovaries and the endometrium in both the early and advanced stages of the disease, which can be used as a new diagnostic criterion. Additionally, there was a violation of lipid peroxidation processes in cancer, which can also be assessed by the IR spectra of saliva lipid extracts.
Conclusions: The combination of spectroscopic data and the results of biochemical analysis of saliva improves the accuracy of diﬀerentiation of the studied groups, which represents a promising direction in the search for new diagnostic markers of ovarian and endometrial cancer.
Ovarian and endometrial cancers are the most common types of gynecological malignant neoplasms [1,2]. The prognosis for most cases of cancer is associated with early detection, which causes certain di-agnostic diﬃculties, especially for ovarian cancer [3–6]. In this regard, the issue of finding new fast and non-invasive diagnostic tools for the detection of ovarian and endometrial cancer is relevant [7,8].
A number of authors show the important role of lipids in the pro-cesses of carcinogenesis and suggest using these indicators in the di-agnosis of ovarian and endometrial cancers [9–27]. Lipids are the main components of the cell membrane, essential for various biological functions, including cell growth and cell division to maintain cell in-tegrity [9,10]. Cholesterol is a precursor of bile acids and steroid hor-mones, it can cause increased tumor angiogenesis, a decrease in tumor
apoptosis and an increase in the proliferation of tumor cells . One of the proposed mechanisms includes the vital role of cholesterol in cell membranes, which can aﬀect various signaling pathways . It is known that increased synthesis of fatty acids is one of the most im-portant deviations in the metabolism of cancer cells and is necessary both for carcinogenesis and for the survival of cancer cells [13–15]. In order to support cell proliferation in cancer, an increase in lipid me-tabolism is necessary [16,17], therefore the level of lipids decreases in the group of patients with malignant tumors . Certain atypical trends are observed in the lipid profiles of the blood plasma of cancer patients [19–26]. The key role of lipid metabolism in metastatic colo-nization has also been shown .
It is known that IR spectroscopy has great potential for analyzing human cells, fluids and tissues . In particular, this method does not require modification of samples, unlike staining methods, and can
reveal information about the biochemical composition, such as protein conformation . This powerful approach based on molecular vibra-tions can be used to diﬀerentiate healthy and tumor tissue, as well as between tumors of varying degrees of malignancy. The use of IR spectroscopy for cancer research has been described, according to which changes in the content of lipids, protein and phosphate groups were detected, especially in the frequencies of nucleic acids [30–38]. However, formalin-fixed tissues were used in these studies, which can aﬀect the chemical composition of the tissue; therefore, it is necessary to apply a complex wax removal protocol that should be optimized for various types of cancer tissues [39,40]. For diagnostic purposes, the use of plasma and serum in combination with IR spectroscopy and classi-fication methods for the detection of ovarian cancer is also described [41–44]. The use of Raman spectroscopy to detect ovarian cancer has been described , in which the ratio of unsaturated lipids to total lipids was measured. However, the study of lipids by the method of IR spectroscopy for cancer of the ovaries and endometrium has not yet been carried out. This method is widely used in the study of biological material, but absorption bands corresponding to fluctuations in lipid functional groups without preliminary processing of samples are not always informative due to overlapping with water absorption bands [46–49]. We have proposed a modification of the Folch method for the quantitative determination of lipids in biological material, in which, after extraction of lipids with chloroform/ethanol, lipids are de-termined using IR spectroscopy . A multifactor regression model was constructed that describes the experimental data with an error of less than 12%.
At present, saliva is used as a promising biological fluid for la-boratory diagnostics [51–58]. It has been shown that saliva IR spec-troscopy can be used to diagnose cancer using the example of lung and breast cancers . The purpose of this work was to use the method of IR spectroscopy to assess changes in the lipid profile of saliva in ovarian and endometrial cancer.