The fidelity of p16 staining as a surrogate marker of human papillomavirus status in fine-needle aspirates and core biopsies of neck node metastases: Implications for HPV testing protocols

Objectives: The importance of detecting human papillomavirus (HPV) in head and neck squamous cell carcinoma (HNSCC) has resulted in a growing expectation for HPV testing of clinical samples. Although testing protocols vary, most pertain to primary tumor biopsies/resections. Testing of fine-needle aspirates and core biopsies (FNACBs) is advantageous, but it is unclear whether technical and biological factors adversely affect the fidelity of HPV detection in these samples. Methods: Data was collected for 85 patients with regionally metastatic HNSCC that had undergone FNACB with HPV analysis as part of clinical care. HPV testing consisted of p16 immunostaining and HPV in situ hybridization (ISH). The FNACBs were compared with the subsequent biopsies/resections for HPV status. Results: p16 staining was present in 60 cases (71%). p16 positivity was predictive of oropharyngeal origin (p < 0.001) and correlated with the presence of HPV by ISH (98% correlation). On comparison of the metastases and primary cancers, the HPV status was concordant in 58 of 59 cases (98%). Conclusions: For patients with metastatic HNSCC, p16 staining reliably reflects the HPV status of the primary tumor. p16 staining of FNACBs may obviate the need for more invasive sampling of the primary cancer solely for the purpose of HPV testing.