Prognostic Role of Porphyromonas gingivalis Gingipain Rgp and Matrix Metalloproteinase 9 in Oropharyngeal Squamous Cell Carcinoma.

BACKGROUND/AIM: The oral bacteria involved in the development of periodontitis alter the tissue conditions and modify immune responses in a way that may also influence tumor development. We investigated the prevalence of R gingipain (Rgp), a key virulence factor of the oral pathobiont Porphyromonas gingivalis, and the tissue-destructive enzymes matrix metalloproteinase 8 (MMP-8) and 9 (MMP-9) in 202 unselected consecutive oropharyngeal squamous cell carcinoma (OPSCC) samples. We further investigated the relationships between these factors and human papillomavirus (HPV) status, Treponema denticola chymotrypsin-like proteinase (Td-CTLP) immunoexpression, clinical parameters, and patient outcome. PATIENTS AND METHODS: Clinicopathological data were derived from university hospital records. Rgp, MMP-8, and MMP-9 immunoexpression was evaluated by immunohistochemistry; the immunohistochemistry of Td-CTLP and HPV has been described earlier for this patient series. Cox regression analysis including death by causes other than OPSCC as a competing risk served to assess sub distribution hazard ratios. RESULTS: In multivariable survival analysis, positive tumoral MMP-9 immunoexpression predicted poor prognosis among all patients [sub distribution hazard ratio (SHR)=2.4; confidence interval (CI)=1.2-4.4, p=0.008], and especially among those with HPV-negative OPSCC (SHR=3.5; CI=1.7-7.3, p=0.001). Positive immunoexpression of Rgp in inflammatory cells was associated with favorable outcome among all patients (SHR=0.5, CI=0.2-0.9, p=0.021) and among those with HPV-negative disease (SHR=0.4, CI=0.2-0.9, p=0.022). CONCLUSION: Our results suggest that tumoral MMP-9 may be related to poor outcome in OPSCC, especially in HPV-negative disease, while Rgp immunoexpression in inflammatory cells is associated here with better disease-specific survival (DSS).

In HPV-negative oropharyngeal squamous cell carcinoma, elevated toll-like receptor 2 immunoexpression may increase the risk of disease-specific mortality.

OBJECTIVES: In oropharyngeal squamous cell carcinoma (OPSCC), toll-like receptors (TLR) 5 and 7 associate with the tumor's human papilloma virus (HPV) status (Jouhi et al., 2017). TLR 2, on the other hand, has been linked to head and neck squamous cell carcinoma (HNSCC), and to oral carcinogenesis (Farnebo et al., 2015; Binder Gallimidi et al., 2015). Here we investigated the presence of TLR 2 and 4 in HPV-positive and HPV-negative OPSCC, and their relationship to opportunistic oral pathogen Treponema denticola chymotrypsin-like protease (Td-CTLP) immunoexpression, clinical parameters, and patient outcome. MATERIALS AND METHODS: Clinicopathological data of 198 unselected consecutive OPSCC patients came from hospital registries. Immunoexpression of TLRs 2 and 4 we evaluated by immunohistochemistry, and earlier in this patient series we studied immunoexpression of Td-CTLP and HPV DNA, HPV mRNA, and p16 status. RESULTS: Immunoexpression of both TLRs 2 and 4 showed a significant association with HPV-status. Strong expression was associated with HPV-positivity and mild expression with HPV-negativity. Patients with strong TLR 2 immunoexpression in the HPV negative subgroup had significantly poorer 5-year DSS (58%) than did patients with mild TLR 2 expression (77%), and strong TLR 2 immunoexpression remained as an independent factor linked to increased disease mortality in the multivariable setting (P = 0.019). No association existed between TLR 2 or 4 and Td-CTLP expression. CONCLUSION: Our results support the role of TLR 2 receptor as a possible target for development of therapeutics as earlier proposed (Farnebo et al., 2015). The involvement of Td and other oral pathogens in carcinogenesis of OPSCC, remains open and calls for further study.

Elevated TLR5 expression in vivo and loss of NF-κΒ activation via TLR5 in vitro detected in HPV-negative oropharyngeal squamous cell carcinoma.

In oropharyngeal squamous cell carcinoma (OPSCC), the expression pattern of toll-like receptors (TLRs), in comparison between human papillomavirus (HPV)-positive and -negative tumors differs. TLRs control innate immune responses by activating, among others, the nuclear factor-κΒ (NF-κΒ) signaling pathway. Elevated NF-κΒ activity is detectable in several cancers and regulates cancer development and progression. We studied TLR5 expression in 143 unselected consecutive OPSCC tumors, and its relation to HPV-DNA and p16 status, clinicopathological parameters, and patient outcome, and studied TLR5 stimulation and consecutive NF-κB cascade activation in vitro in two human OPSCC cell lines and immortalized human keratinocytes (HaCat). Clinicopathological data came from hospital registries, and TLR5 immunoexpression was evaluated by immunohistochemistry. Flagellin served to stimulate TLR5 in cultured cells, followed by analysis of the activity of the NF-κB signaling cascade with In-Cell Western for IκΒ and p-IκΒ. High TLR5 expression was associated with poor disease-specific survival in HPV-positive OPSCC, which typically shows low TLR5 immunoexpression. High TLR5 immunoexpression was more common in HPV-negative OPSCC, known for its less-favorable prognosis. In vitro, we detected NF-κΒ cascade activation in the HPV-positive OPSCC cell line and in HaCat cells, but not in the HPV-negative OPSCC cell line. Our results suggest that elevated TLR5 immunoexpression may be related to reduced NF-κΒ activity in HPV-negative OPSCC. The possible prognosis-worsening mechanisms among these high-risk OPSCC patients however, require further evaluation.

Treponema denticola chymotrypsin-like protease as associated with HPV-negative oropharyngeal squamous cell carcinoma.

BACKGROUND: An opportunistic oral pathogen, Treponema denticola (Td), has been linked to orodigestive carcinogenesis, but its role in oropharyngeal squamous cell carcinoma (OPSCC) has remained open. We evaluated the presence of Td chymotrypsin-like protease (Td-CTLP) in a series of 201 unselected consecutive OPSCC patients, and the relation of the Td-CTLP to human papillomavirus (HPV) status, to expression of toll-like receptors (TLR) 5, 7, and 9, and to clinical parameters and patient outcome. METHODS: Clinicopathological data came from hospital registries. The expression of cell surface-bound Td-CTLP was evaluated by immunohistochemistry. Immunoexpression of TLRs 5, 7, and 9, and HPV status we studied earlier in this patient series. RESULTS: We detected Td-CTLP in 81% of the OPSCC, and especially in HPV-negative tumours (48% of all OPSCCs). Among the HPV-positive tumours (52% of all OPSCCs), low Td-CTLP expression associated with low TLR 5 and high TLR 7 expression. Among those HPV-negative, higher TLR 5 and lower TLR 7 expression associated with high Td-CTLP expression. Strong Td-CTLP expression associated with poor disease-specific survival, but no similar association among HPV-positive and HPV-negative subgroups emerged. CONCLUSIONS: Td-CTLP was highly expressed in OPSCC and was associated with the HPV status of tumour tissue.