Macrophages expressing TREM-1 are involved in the progression of HPV16-related oropharyngeal squamous cell carcinoma

Abstract

Introduction: Many types of research have been performed to improve the diagnosis, therapy, and prognosis of oropharyngeal carcinomas (OP-SCCs). Since they arise in lymphoid-rich areas and intense lymphocytic infiltration has been related to a better prognosis, a TREM-1 putative function in tumour progression and survival has been hypothesized.

Materials and methods: Twenty-seven human papillomavirus (HPV) 16⁺ OP-SCC specimens have been analyzed to relate TREM-1 expression with histiocytic and lymphocytic markers, HPV presence and patients' outcome.

Results: No differences have been shown between intratumoral and stromal CD4⁺ cells, while intratumoral CD8⁺ lymphocytes are higher with respect to the tumour stroma (p = .0005). CD68⁺ cells are more than CD35⁺ and TREM-1⁺; their presence is related to CD35^± and TREM-1^± histiocytes (p = .005 and .026, respectively). Intratumoral CD4⁺ lymphocytes are higher in p16⁺ cases (11/27) than in p16^- (p = .042); moreover, p16 positivity correlates to a better survival (p = .034). CD4⁺, CD8⁺ and CD35⁺ cells have no impact on survival, while CD68 expression heavily influences progression and bad outcome (p = .037). TREM-1 positivity also leads to worst overall survival (p = .001): peritumoral expression and death-cause relationship are always significant, particularly when the cause is OP-SCC (p = .000).

Conclusion: While p16 shows to better stratify HPV16⁺ patients' outcome, TREM-1⁺ macrophages suggest their key importance in HPV-related OP-SCCs progression.KEY MESSAGESTREM-1 positivity correlates to the worst overall survival of HPV16-positive OPSCCs-affected patients.p16-positive HPV16 related OPSCCs patients have a better prognosis with respect to p16-negative ones.

Keywords: Human papillomavirus (HPV); oropharyngeal squamous cell carcinoma (OP-SCCs); peritumoral and intratumoral infiltration; triggering receptor expressed on myeloid cells-1 (TREM-1); tumoral microenvironment (TME).

Figure 1.

Representative haematoxylin and eosin (H-E) staining and expression of peritumoral and intratumoral markers in low and high progression OP-SCCs. Top panel: H-E staining. 20× (a, b) and 40× (a’, b’). Middle panel: peritumoral infiltration expression. CD4: 20× (c, d) and 40× (c’, d’); CD8: 20× (e, f) and 40× (e’, f’); TREM-1: 20× (g, h) and 40× (g’, h’); CD35: 20× (i, j) and 40× (i’, j’); CD68: 20× (k, l) and 40× (k’, l’). Bottom panel: intratumoral markers expression. CD4: 20× (m, n) and 40× (m’, n’); CD8: 20× (o, p) and 40× (o’, p’); p16: 20× (q, r) and 40× (q’, r’). The black boxes in the 20× fields correspond to the 40× magnification fields. Markers have been developed with 3,3’-diaminobenzidine. Scale bar: in the 20× fields,50 µm; in the 40× fields, 20 µm.

Figure 2.

Graphical representation of (a) overall survival: the Kaplan–Meier method reveals a total 5-years overall survival of 51.85% (14 out of 27; 95% CI = 47.5–83.3); (b) cumulative incidence of death from any cause: the 5-years cumulative incidence of death, calculated from the date of diagnosis to the date of death (end of follow-up), evidences that a total of 13 (48.15%) patients out of 27 died; (c) cumulative incidence of death stratified by cause: the 5-years cumulative incidence of death from oropharyngeal cancer (persistence and relapses) is 29.63% (8 out of 27; 95% CI = 14.4–49.5), while death from other tumours and other causes is 18.52% (5 out of 27; 95% CI = 0.7–28.1).