br Additionally the intensity ratio of cm
Additionally, the intensity ratio of 2923/2957 cm−1 is calculated. This ratio is statistically significantly reduced for endometrial cancer (−16.2% compared with the control group) and for ovarian cancer (−23.9%). When calculating the concentration of lipids, a decrease by 21.1% for endometrial cancer and by 23.7% for ovarian cancer com-pared with the control group was noted, while the changes are not statistically significant. At the same time, the proposed intensity ratio of 2923/2957 cm−1 rather accurately characterizes the change in lipid content in oncological diseases, which makes it possible to use it instead of the traditional definition of lipid content by an enzymatic method. It should be noted that for the ratio of 1458/1396 cm−1, which also re-presents the ratio of the intensity of the E 64d bands of methylene and methyl lipid groups, no statistically significant diﬀerences between the studied groups were detected (Table 2).
Since the intensity and area of the peaks in the IR spectra change unidirectional, in the course of further studies, only the intensity of the corresponding absorption bands was estimated. In particular, a com-parison was made of the intensity of the absorption bands in the spectra of patients with oncological diseases, non-malignant pathologies and healthy ones (Fig. 2A–F).
It is shown that the intensity of most of the absorption bands is maximally reduced in case of non-malignant pathologies of the ovaries and endometrium. Only for the absorption band 1458 cm−1, a statis-tically significant diﬀerence between malignant and non-malignant ovarian pathologies was established (Fig. 2B); in other cases,
diﬀerences are observed only in comparison with the control group (Fig. 2A, C–F).
It is interesting to note that with the progression of the disease, a further decrease in the intensity of the absorption bands in the IR spectra is observed. However, only a decrease in the intensity of the absorption bands of 2853 and 2923 cm−1 for ovarian cancer and the intensity ratio of 2923/2957 cm−1 in all cases are statistically sig-nificant (Table 2). Thus, the intensity ratio of 2923/2957 cm−1 natu-rally decreases with the transition from the control group to non-ma-lignant pathologies of the endometrium and ovaries, and then to oncological pathologies, reaching maximum diﬀerence with the control group at advanced stages of the disease (Fig. 3). This allows using this ratio as a potentially informative marker in the clinical laboratory di-agnosis of ovarian and endometrial cancer.
In addition to determining the total lipid content, analysis of lipid peroxidation products in the saliva of patients of the studied groups was also carried out (Tables 3 and 4). It has been shown that in ovarian and endometrial cancer there is an increase in lipid peroxidation processes: the content of primary products (diene conjugates) decreases, but the level of secondary products (triene conjugates and Schiﬀ bases) in-creases, however the growth of the final MDA product is not statistically significant (Table 3).
With the progression of endometrial cancer, an equilibrium of lipid peroxidation processes is shifted towards more toxic triene conjugates and Schiﬀ bases (Table 4), while the changes compared to the control group are statistically significant for both the early and advanced stages of the disease. The level of MDA for stage T2-3N1-xM0 even decreases, which again confirms the accumulation of Schiﬀ bases as lipid perox-idation products. There is a significant increase in the level of secondary lipoperoxidation products for ovarian cancer already at an early stage of the disease, which is somewhat reduced at advanced stages (Table 4). However, in this case, the level of MDA during the transition from the stage T1N0M0 to T2-3N1-xM0 practically does not change, which means a shift in the equilibrium of lipid peroxidation processes to the final product (MDA).
The calculation of correlation coeﬃcients showed (Table 5) that the level of diene conjugates for the control group according to biochemical and spectroscopic data correlate, whereas with endometrial and ovarian pathologies there is no correlation. Apparently, with oncolo-gical diseases, the balance of lipid peroxidation processes shifts towards
Absorption band intensities in the IR spectra of saliva depending on the stage of the disease according to the TNM system.
Wavenumber, Endometrial Cancer
Note. * - the changes compared with the control group are statistically significant (p < 0.05).
- change compared with the control group,%.