Neoplastic cells exhibit various genetic alterations, including gene rearrangements, amplifications, and mutations, which disrupt critical pathways controlling cell growth, survival, and metastasis. These alterations, when common in specific tumor types, can serve as biomarkers for detection and targeted therapy [8, 9]. Diagnostic and prognostic biomarkers, such as serum β2-microglobulin (β2-M), play a crucial role in identifying individuals at risk, diagnosing early-stage cancers, guiding treatment decisions, and monitoring responses [10]. β2-M, a small protein component of the HLA antigen, is expressed on nearly all nucleated cells and can be detected in bodily fluids. Elevated serum levels of β2-M in cancer may result from increased cellular activity, membrane turnover, or altered HLA expression, potentially helping tumors evade immune detection. These characteristics suggest a correlation between β2-M levels and tumor burden and cellular turnover, highlighting its potential as a valuable tumor marker in oral carcinoma research [11–13].
Our study revealed no statistically significant associations between age groups (20–39 and 40–60 years) and the likelihood of being a case or control of oral carcinoma. While 19% of individuals aged > 20–39 years are cases, while 26% are controls, the prevalence of NAFLD shifts notably in the 40–60 years age group, with 81% of the patients and 74% of the controls. The chi-square test with X = 1.405 and a p value of 0.2359 underscores this lack of significance, indicating that older individuals are disproportionately more likely to be cases than younger individuals are. The Sequeira et al. [10] study involved 25 patients with OSCC aged 30–71 years, with a maximum incidence of 41–60 years and more commonly occurring in males, which is in accordance with the findings of various epidemiological studies of oral cancer performed in India [14–17].
The study highlights a notable difference in the prevalence of alcoholism and smoking between cases and controls. Specifically, 57% of the patients reported alcoholism, whereas 12% of the controls reported alcoholism; 72% of the patients were smokers, while 15% were controls. These substantial differences (alcoholism: p < 0.0001; smoking: p < 0.0001) underscore the robust association between these behaviors and the studied conditions. The findings suggest that individuals with alcoholism and smoking habits are significantly more likely to develop oral carcinoma than are those without these risk factors. Our study aligns with findings from Kulkarni et al. [18], who also reported a significant prevalence of alcoholism and smoking among oral carcinoma patients compared to controls. Kulkarni et al. reported that the primary harmful behavior observed in both groups was tobacco chewing, with prevalence rates of 83.33% in Group A and 73.33% in Group B [18]. Additionally, Kulkarni et al. noted tobacco chewing as a predominant habit among their subjects, reinforcing its role as a major risk factor for oral cancer, especially in male patients [18].
The distribution of chief complaints in our study highlights significant disparities between cases and controls. Among the patients, various symptoms were prominently observed: 65% experienced difficulty swallowing, 51% had neck swelling, 73% reported pain swallowing, 33% had difficulty with tongue protrusion, 40% had hoarseness of voice, 26% had respiratory distress, 55% had throat pain, 29% had earache, 61% had a sore throat, 35% had excessive salivation, 47% had trismus, 86% had ulcers, and 32% had bleeding. In contrast, none of these symptoms were reported in the controls. This stark contrast underscores the strong association between these symptoms and oral carcinoma, indicating their utility as critical indicators in clinical diagnosis and management. Furthermore, our study comprehensively compared examination findings between cases and controls and revealed substantial differences. Patients exhibited a significantly lower Karnofsky Performance Status score (60.4 ± 10.2) than did controls (90.5 ± 5.2), with a t value of 26.29 and a p value less than 0.0001, indicating a pronounced decline in functional status among patients. Poor oral hygiene was uniformly prevalent in cases (100%) versus controls (26%), with a chi-square statistic of 117.5 and a p value less than 0.0001, emphasizing a robust association with oral hygiene status. All patients were diagnosed with squamous cell carcinoma tumors, which were characterized by an average size of 3.5 ± 1.2 cm and irregular margins in 73% of the patients. Additionally, 41% of the patients showed involvement of surrounding areas, and 88% had local/regional lymph node engagement, with an average of 2.03 ± 1.17 lymph nodes affected and an average size of 2.38 ± 0.82 cm. According to the AJCC 2018 staging system, 62% of patients were classified as Stage II, 30% as Stage III, and 8% as Stage IV, indicating an advanced disease presentation compared to that of the controls. These findings collectively underscore the severe clinical profile and advanced stage of oral carcinoma among patients in our study compared to controls. Rajapakshe et al. [19] and Geum et al. [20] underscored the pivotal role of TNM stage in influencing the prognosis of OSCC patients. According to Suresh et al. [21], there was a notable decrease in overall survival (OS) rates with advancing stage (P < 0.001). Rogers et al. [22] reported a stark difference in 5-year OS between OSCC patients without cervical lymph node metastasis (87%) and those with metastasis (54%). Furthermore, the OS rates varied significantly across lymph node stages: 87% for N0, 68% for N1, and 40% for N2-3, as observed in Suresh et al.'s study [21]. These results reaffirm the significant prognostic impact of cervical lymph node stage in patients with OSCC (P < 0.001, log-rank test). Our study contrasts significantly with Pires et al.’s findings across several key parameters. Pires et al. [23] presented findings on various types of carcinoma: microinvasive carcinoma affects males and females equally, with a mean age of 67.2 years (SD ± 13.05). The mean duration of complaint was 18.4 months (SD ± 22.7), with leukoerythroplastic areas observed in 73.1% and ulcerated areas in 50% of the patients. The tumors predominantly affected the border of the tongue (56%) and lower lip (16%), with a mean size of 1.9 cm (SD ± 1.6). Most patients reported no tobacco use (52.6%) or alcohol use (53.3%). Verrucous carcinoma predominantly affected elderly females (mean age 73.2 years, SD ± 14.3), presenting with leukoerythroplastic (78%) and ulcerated (56%) areas. The tumors were located mainly on the alveolar mucosa/gingiva (44.4%) and buccal mucosa/buccal sulcus (33.3%), with a mean size of 3.8 cm (SD ± 1.3). Tobacco use was reported in 60% of the participants, but alcohol use was minimal (33.3%). Spindle cell carcinoma primarily affects male adults (mean age 57 years, SD ± 10.4), who present with ulcerated areas (80%) and various affected sites, including the border of the tongue (40%) and alveolar mucosa/gingiva (20%). The mean tumor size was 4.3 cm (SD ± 1.5), and all patients reported both tobacco and alcohol use. The nasaloid OSCC patients included a male with a 10 cm lesion on the buccal mucosa and a female with a 2.5 cm lesion on the border of the tongue, both of which presented as ulcerated and leukoerythroplinous. One patient reported tobacco use. Papillary OSCC was observed in a 64-year-old male on the buccal mucosa, presenting as a 5 cm ulcerated lesion in a patient who was not a tobacco or nonalcoholic user. These comprehensive findings underscore the severe clinical presentation and advanced stage of oral carcinoma among patients in our study, reflecting a more challenging disease profile than reported by Pires et al. [23]. Sequeira et al. [10] observed a significant association between serum β2-M levels and nodal status in their study, suggesting its potential as a predictive marker for nodal involvement, which is crucial for prognosis and postsurgical outcomes in patients with carcinoma. Similarly, our study revealed a progressive increase in the serum β2-M concentration across clinical stages of OSCC, with a notable increase observed in stage IV patients (44%). This pattern aligns with findings by Kadam et al. [24] and Wilma et al. [25], who reported higher β2-M levels in OSCC with combined endophytic and exophytic growth patterns than in those with purely endophytic or exophytic growth patterns. Elevated β2-M levels have been linked to various lymphoid malignancies, such as multiple myeloma and B-cell non-Hodgkin's lymphoma [26–29]. Additionally, studies such as those by Hagberg et al. [30], Chronowski et al. [31] and Constantinides et al. [32] have associated elevated β2-M levels with disease stage and prognosis in Hodgkin's disease, highlighting its prognostic relevance across different cancers.
A comparison of biomarker levels between patients and controls revealed substantial differences. Specifically, LSA scores were significantly greater in patients (mean: 1932.69, SD: 2000.86) than in controls (mean: 1182.73, SD: 1112.77), with a t value of 3.276 and a p value of 0.0012. Similarly, β2 M levels were markedly greater in patients (mean: 69.21, SD: 50.81) than in controls (mean: 1.46, SD: 4.94), with a higher t value of 13.27 and a p value less than 0.0001, highlighting a stronger association. Our study, in comparison to that of Agrawal et al., highlights significant differences in biomarker levels between cases and controls. Agrawal et al. [33] reported that the serum β2-microglobulin concentration significantly differed across groups: 1.88 ± 0.82 µg/ml in controls, 2.23 ± 0.84 µg/ml in patients with oral leukoplakia, and 3.23 ± 0.96 µg/ml in patients with oral squamous cell carcinoma (OSCC). The increase in β2-microglobulin levels from controls to patients with OSCC was highly statistically significant (p < 0.001), and patients with OSCC showed a significant increase in the β2-microglobulin level compared to patients with oral leukoplakia (p < 0.05). Although β2-microglobulin levels were greater in patients with oral leukoplakia than in controls, this difference was not statistically significant (p > 0.05). Additionally, β2-microglobulin levels were found to increase significantly with age in the control group. These results suggest that both LSA and β2 M are robust biomarkers for distinguishing between individuals with and without oral carcinoma, underscoring their potential diagnostic utility.
The current study reveals robust diagnostic performance metrics for β2 M and LSA levels in oral carcinoma patients. β2 M exhibited exceptional diagnostic accuracy, with an AUC of 0.999 (95% CI: 0.994-1.000), an optimal cutoff of 2714.20, a sensitivity of 97.87%, and a specificity of 100.00%. This indicates a near-perfect ability to differentiate patients from controls with minimal misclassification. The LSA also showed excellent diagnostic performance, with an AUC of 0.945 (95% CI: 0.900–0.990), an optimal cutoff of 2234.84, a sensitivity of 80.85%, and a specificity of 94.34%, which was slightly less accurate than that of β2 M but still highly effective. Moreover, correlation analysis revealed a very strong positive correlation for β2 M (r = 0.97, 95% CI = 0.95–0.98, p = 0.006) and a strong positive correlation for LSA (r = 0.86, 95% CI = 0.79–0.90, p = 0.008) with the condition studied. These findings underscore the reliability of β2 M and LSA levels as diagnostic markers, with β2 M demonstrating a particularly robust correlation and diagnostic accuracy in oral carcinoma. Similarly, Viashali and Tupkari et al. similarly demonstrated a notable association between serum β2 M levels and the histological grade of SCC, suggesting that this biomarker is a sensitive tool for diagnosis, analysis, and prognosis [34].
This study highlights the potential of serum β2 M and LSA as diagnostic biomarkers for oral carcinoma. The marked increase in the expression of these biomarkers in patients, along with their strong correlations with advanced AJCC stages, underscores their clinical relevance in assessing disease severity. The high diagnostic accuracy of the β2 M and LSA, demonstrated by their AUC values and optimal cutoffs, suggest their effectiveness in distinguishing patients from controls with high sensitivity and specificity. Incorporating these biomarkers into clinical practice could improve early detection, patient prognosis, and treatment monitoring in oral carcinoma patients, ultimately enhancing patient outcomes. However, further research should validate these findings in larger cohorts and explore their longitudinal applicability to confirm their clinical utility.