Loss of CD169 Subcapsular Macrophages during Metastatic Spread of Head and Neck Squamous Cell Carcinoma.

OBJECTIVE

The purpose of this study is to assess CD169 expression in metastatic and nearby tumor-free lymph nodes of patients with head and neck squamous cell carcinoma (SCC).

STUDY DESIGN

Retrospective analysis based on immunohistochemistry.

SETTING

Tertiary care center.

SUBJECTS AND METHODS

The abundance of CD169 cells in the subcapsular sinuses (SCSs) of lymph nodes was assessed immunohistochemically in paraffin-embedded tissue samples derived from 22 patients with oral cavity and oropharyngeal SCC.

RESULTS

SCSs of lymph nodes harboring metastatic SCC contained significantly fewer CD169 macrophages (106.5 ± 113.6 cells/mm) compared to nearby tumor-free lymph nodes (321.3 ± 173.4 cells/mm, < .001). This observation extended to 21 of the 22 cases investigated. In addition, 6 patients who later developed recurrent disease contained lower numbers of CD169 cells (268.6 ± 169.5 cells/mm) in nearby tumor-free lymph nodes compared to 341.0 ± 176.1 cells/mm in those who remained disease free ( = .399). Human papillomavirus (HPV)-positive patients (n = 4) had a 6-fold lower number of CD169 cells in metastatic nodes (61.2 ± 85.5 cells/mm) compared to nearby tumor-free lymph nodes (369.5 ± 175.5 cells/mm, = .028). In comparison, HPV-negative patients had only a 3-fold reduction (116.6 ± 118.5 cells/mm vs 310.6 ± 176.2 cells/mm, < .001).

CONCLUSION

Metastatic spread of SCC to regional lymph nodes is associated with lower abundance of CD169 macrophages in the SCSs of draining lymph nodes. These results set the stage for an in-depth investigation into the mechanism(s) by which metastatic SCC controls CD169 macrophage abundance and its significance as it relates to prognosis and treatment response.