Comparative Analysis of Oral Prevotella intermedia, Tannerella forsythia, Streptococcus sanguinis, and Streptococcus mutans in Patients with Esophageal Squamous Cell Carcinoma and Healthy Controls in Mthatha, South Africa

The microbiome plays a crucial role in cancer development, influencing fundamental processes such as cell proliferation, apoptosis, immune system regulation, and host metabolism. Recent studies have highlighted a possible relationship between esophageal cancer and the oral microbiota, making oral microflora a possible risk factor. The bacteria Prevotella intermedia, Tannerella forsythia, Streptococcus sanguinis, and Streptococcus mutans, implicated in various oral pathologies, were of interest in this study, which was initiated to examine their potential role in the etiology of esophageal squamous cell carcinoma (ESCC). To achieve this, a case-control design was used, with whole saliva samples collected from 24 healthy controls and 24 patients with esophageal squamous cell carcinoma. DNA was then extracted, and real-time PCR was performed to quantify the presence of the targeted bacteria in both groups. The results showed that all the bacteria studied were present in the saliva of both patients with ESCC and healthy controls. However, expression levels were significantly higher in patients with ESCC. Specifically, a marked increase in the presence of P. intermedia, T. forsythia, S. sanguinis, and S. mutans was observed in the patients with cancer compared to the healthy controls. In short, this study highlights a significant imbalance in the microbial flora, with an increased abundance of selected bacteria in patients with ESCC. The monitoring of these bacteria could thus be exploited to track patients who are at risk. Their integration into diagnostic and therapeutic strategies would offer new prospects for the early diagnosis and improved prognosis of patients at risk of ESCC.