Sphingolipids signature in plasma and tissue as diagnostic and prognostic tools in oral squamous cell carcinoma

Enzymes related to sphingolipids metabolism has been suggested as altered in oral squamous cell carcinoma (OSCC). However, clinical relevance of diverse sphingolipids in OSCC is not fully known. Here, we evaluated sphingolipidomics in plasma and tumor tissues as a tool for diagnosis/prognosis in OSCC patients. Plasma was obtained from 58 controls and 56 OSCC patients, and paired tumor and surgical margin tissues (n = 42). The levels of 28 sphingolipids molecules were obtained by mass spectrometry. Furthermore, sphingolipids were analyzed with clinical and pathological characteristics to search the potential for diagnosis and prognosis. Lower levels of 17 sphingolipids was found in the plasma of OSCC patients compared to controls while four were elevated in tumor tissues. C18:0 dyhidroceramide and C24:0 lactosylceramide in plasma were associated with perineural invasion, while tissue levels of ceramide and dyhidroceramide were associated with advanced tumor stage and perineural invasion. High plasma levels of C24:0 ceramide (HR = 0.10, p = 0.0036) and C24:1 glucosylceramide (HR = 6.62, p = 0.0023), and tissue levels of C24:0 dyhidroceramide (HR = 3.95, p = 0.032) were identified as independent prognostic factors. Moreover, we identified signatures composed by i) sphinganine-1-phosphate and C16 ceramide-1-phosphate in plasma with significant diagnostic accuracy, while ii) C24:0 ceramide, C24:0 dyhidroceramide, and C24:1 glucosylceramide plasma levels, and iii) C24:0 dyhidrosphingomyelin and C24:0 ceramide tissue levels showed value to predict survival in patients aged 60 years or older. We proposed the sphingolipids signatures in plasma and tumor tissues as biomarkers candidates to diagnosis and prognosis in OSCC.