**4. Serum biomarkers**

During tumor development, the release of synthesized markers into the circulation results in an increase in markers in cancer patients' serum, which can be used to predict the development of the cancer itself. The secreted origins of tumor-specific or tumor-associated serum biomarkers are known. Taking regular measurements of these biomarkers could provide valuable insight into how patients respond to anticancer treatments in the long run. Both the progression of the disease and its treatment are discussed in detail. Adiponectin is a protein hormone that can be found in the bloodstream and performs a number of different functions. It aids in the digestion of glucose and fatty acids in the bloodstream. Guo et al. discovered that the levels of adiponectin were higher. The incidence of tongue squamous cell carcinoma (TSCC) has dropped significantly. Hypoadiponectinemia has also been associated with lymphoma in some studies. The prognosis for TSCC metastasis is abysmal. Another protein, hemoglobin (Hb), being associated with an increased risk of oral cancer in the opposite direction. Reduced hemoglobin levels and anemia have been linked to increased tumor oxygenation and lymph node metastasis, and Hb corrections have been shown to improve prognosis in cancer patients.

Low hemoglobin levels indicate advanced OSCC, especially in larger tumors requiring more radial treatment. Pro-inflammatory cytokines are a group of small proteins that play a role in inflammation. Oral cancer is the most common link. In a prospective study, Schiegnitz et al. looked at the role of IL-6, 8, soluble IL-2 receptor (SIL-2R), MHC class I polypeptide-related sequence B (MICB), and tumor necrosis factor alpha (TNF-a) in OSCC. According to their findings, all of these biomarkers showed an upward trend in serum samples from oral cancer patients. Promising OSCC prognostic indicators have been identified as IL-6 and SIL-2R. Chang et al. also discovered a link between oral cancer clinical manifestations and blood levels of 12 cytokines. However, the results of a different study refuted these assertions. Individual or panels of serum cytokines are not appropriate oral cancer biomarker candidates due to these discrepancies and heterogeneous literature searches. However, it has been suggested that some inflammatory and immune system-related proteins are self-contained. Oral cancer metastasis indicator C-reactive protein (CRP), for example, is an IgG analog that stimulates the release of pro-inflammatory cytokines. CRP is an inflammatory marker that has been linked to a variety of diseases and cancers. Previous research has looked into the relationship between OSCC size, stage, and subsequent survival and CRP serum levels. Elevated serum CRP has been proposed as a predictor of poor prognosis and a low survival rate in oral cancer patients. The soluble protein Decoy receptor 3 (Dcr3) prevents programmed cell death. It is a member of the TNF receptor family. Several cancers have been found to have a high rate of cell death and amplification. According to estimates, when lymph node metastasis occurs at the same time as OSCC, the prognosis is worsened. In this context, serum MMPs have also been investigated. Liu et al. investigated the link between MMP-9 and pathological manifestations in oral cancer patients in a survey. A higher level of this factor was discovered to be linked to a shorter life expectancy. On the other hand, some of these serum proteins have been suggested as potential biomarkers for OSCC diagnosis but not prognosis prediction. For example, MMP-3 levels have not been linked to OSCC clinicopathological features. As potential biomarkers, different levels of growth factors in the serum of oral cancer patients have been proposed. Vascular. In various tumor propagation processes, the vital protein endothelial growth factor (VEGF) is thought to induce angiogenesis. Nodal metastasis and advanced OSCC have been linked to higher levels of this factor. Furthermore, in a 6-month cumulative survival study, the results of a 12-month study OSCC serum insulin-like growth factor (IGF) and survival were found to be strongly linked.

*Way to Cure Oral Squamous Cell Carcinoma with Theranostics and Nanoparticular Approaches DOI: http://dx.doi.org/10.5772/intechopen.100181*
