SODs are the body's primary line of defense versus ROS-induced damage [10] , Catalytically converting oxygen into hydrogen peroxide is the job of SOD, an anti-oxidant enzyme [11]. SOD declines with age, and that means more disease-inducing free radicals [12]. However, the fact that SOD activity was found to be lower than expected in the study hints at a greater consumption of antioxidative enzymes due to elevated oxidative stress [13].

In contrast to our study, previous research conducted by Islam et al. demonstrated reduced activities of CuZn-SOD and Mn-SOD in cancer cells, indicating a potential role for SOD in promoting the reversal of cancer cell phenotypes. These findings suggested that endogenous antioxidant enzymes could potentially regulate cancer development and be targeted for cancer treatment [14]. Similarly, Balaky et al. conducted a study that frequently documented the overexpression of Superoxide dismutase 1 (SOD1) in lung cancers. The study highlighted the essential role of SOD1 in the development of lung disease. These studies present contrasting results to our findings regarding the SOD enzyme levels in lung cancer patients who smoke and non-smoke [15].

Cholesterol-derived vitamin D3 regulates the epigenome and transcriptome in many different human tissues and cells, including cancerous tumor cells. The metabolite 1,25(OH)2D3 and its high-affinity receptor VDR (Vitamin D receptor) are responsible for this control [16].

Vitamin D's effect on cancer has been studied in a number of in vitro and in vivo experiments. These studies have demonstrated that vitamin D exhibits anti-metastatic effects, particularly in lung cancer, as well as other cancer types. Vitamin D has been found to suppress cell growth and reduce invasiveness in lung cancer cells during in vitro investigations. Furthermore, research has established a correlation between vitamin D levels and overall survival in individuals with lung cancer [17]. A lack of vitamin D has been linked to a higher chance of acquiring cancer and a greater probability of dying from the condition, according to research by [J. B. Gibbons et al.,] [18]. A study conducted by (Muller DC) found no evidence of a relationship between the levels of vitamin D in the bloodstream with the possibility of lung cancer at a later stage [19]. This suggests that circulating vitamin D concentrations may not be indicative of the likelihood of a subsequent lung cancer diagnosis.

Apart from its role as an antioxidant that helps reduce oxidative stress and inhibit lipid oxidation, vitamin D3 also plays a crucial role in various physiological processes. These include cell differentiation, regulation of growth and reproduction, support for the immune system, protection against DNA damage in cells, as well as the suppression and prevention of cancer cells [20].

Vitamin E consists of eight naturally occurring compounds that share similar chemical structures. It serves as a crucial dietary antioxidant, found in vegetable sources, nuts, and oils. The antioxidant properties of vitamin E have been associated with numerous health benefits, including its ability to reduce inflammation, fight against cancer, and provide neuroprotective effects [21].

Our study suggests that individuals who are smokers or have lung cancer tend to exhibit lower levels of vitamin E compared to healthy individuals. This finding aligns with the research conducted by (Zabłocka-Słowińska K,) which reported a reduction in vitamin E levels among all patients diagnosed with lung cancer [22].

Vitamin E is essential because it prevents further oxidative damage by neutralizing lipid peroxyl radicals and breaking the chain reaction of peroxidation. The significant decrease in serum levels of vitamin E observed may be attributed to oxidative stress, which can be affected by the presence of cancer and/or metabolic changes. Another possible explanation for the lower concentration of vitamin E is a change in the distribution of alpha-tocopherol. Alpha-tocopherol is predominantly found in the LDL-C fraction of the blood, and as serum lipid levels increase, it tends to move from cellular membranes to circulating lipoproteins. Insufficient levels of vitamin E can make individuals more susceptible to dyslipidemia-related factors [22].

L-ascorbic acid, commonly known as vitamin C, has been identified as a crucial element in the management of scurvy [23]. Vitamin C has several significant functions, with its most notable roles including neutralizing free radicals, regenerating vitamin E, acting as a cofactor for hydroxylase enzymes involved in collagen and neurotransmitter synthesis, and regulating gene expression [24]. Those with active inflammation and cancer, particularly haematological malignancies, have been found to have lower levels of plasma and cellular ascorbate, according to research by (L. Zhu and L. Chen). Ascorbate levels drop when a person is sick, and this is thought to be due to increased turnover brought on by oxidative and metabolic stress [25].