Different densities of Langerhans cells among oral squamous cell carcinoma, lip squamous cell carcinoma and oral potentially malignant disorders: Systematic review and network meta-analysis.

OBJECTIVE

to evaluate whether Langerhans cells (LC) (CD1a+, CD207 +) show quantification differences in oral squamous cell carcinoma (OSCC), lip squamous cell carcinoma (LSCC), and oral potentially malignant disorders (OPMDs), due to previously conflicting results.

DESIGN

PubMed, Scopus, Embase, Lilacs, and Web of Science were the databases searched. The protocol was registered in the Open Science Framework (OSF). Rayyan software was used for duplicate removal. Risk of bias was assessed using the Joanna Briggs Institute (JBI) scale for cross-sectional studies. Meta-analyses were conducted using R software (v3.6.3) with the "NETMETA" package. Quality of evidence was evaluated using the CINeMA tool. In total, 26 articles were included for qualitative and 14 articles for quantitative analysis

RESULTS

Higher CD1a+ and CD207 + LC levels were observed in low-grade OSCC compared to well and moderately differentiated OSCC. In addition, reductions of CD1a+ and CD207 + LC were associated with locoregional metastasis to lymph nodes. Among OPMDs, oral lichen planus (OLP) showed the highest CD1a+ and CD207 + density. Significant reductions in LC counts were noted in oral leukoplakia (OL), oral submucous fibrosis (OSF), and OSCC. In LSCC, CD1a+ LCs were significantly reduced compared to actinic cheilitis (AC). Sampling and statistical biases were identified in 7 and 17 studies respectively.

CONCLUSION

Differences in CD1a+ and CD207 + LC densities among OSCC, LSCC, and OPMDs may cooperate in understanding of their immunopathogenesis and support diagnostic and therapeutic strategies in these conditions. Furthermore, CD1a+ and CD207 + density reduction may have the potential to be used as a biomarker for oral malignant transformation. In general, a high confidence rate was observed for CD207 + LC and a moderate confidence for CD1a+ LC was noted.