Meaningful advances in targeted therapy for head and neck squamous cell carcinoma (HNSCC) have been hampered by limited availability of robust preclinical models for translational research. Using an impressive array of in vitro and in vivo preclinical HNSCC models, Smith and colleagues demonstrated the efficacy of alpelisib and tipifarnib combination therapy through sustained mTOR inhibition in PIK3CA/HRAS-dysregulated HNSCC, including preliminary evidence of robust antitumor activity in a patient enrolled in a precision medicine trial. This study in this issue of Cancer Research illustrates the value of preclinical avatars for informing biomarker-driven clinical trials to advance precision medicine in HNSCC and other cancers. See related article by Smith et al., p. 3252.

High rates of recurrence and distant metastasis are a foremost challenge in the management of adenoid cystic carcinoma (ACC), occurring in approximately 40% of all ACC patients. Despite the morbidity and mortality resulting from recurrent/metastatic (R/M) disease, there are no FDA-approved systemic agents for these patients. In this review, we summarize pertinent ACC pathophysiology and its implications for different systemic treatment regimens in R/M ACC. We review the evidence for the most widely used systemic agents - cytotoxic chemotherapy and tyrosine kinase inhibitors (TKIs) targeting VEGFR - in addition to immune checkpoint inhibitors and non-TKI biologic agents. Exciting emerging targets for R/M ACC, including inhibitors of Notch signaling, stemness, PRMT5, and Axl, are also discussed. Lastly, we review local therapies for small-volume lung disease in patients with oligometastatic ACC, specifically pulmonary metastasectomy and stereotactic body radiation therapy (SBRT). Future development of targeted molecular agents which exploit the underlying biology of this disease may yield novel therapeutic options to improve clinical outcomes in patients with R/M ACC.

Fanconi anemia, the most frequent genetic cause of bone marrow failure, is characterized by an extreme predilection toward multiple malignancies, including a greater than 500-fold incidence of head and neck squamous cell carcinoma (HNSCC) relative to the general population. Fanconi anemia-associated HNSCC and esophageal SCC (FA-HNSCC) often present at advanced stages with poor survival. Surgical resection remains the primary treatment for FA-HNSCC, and there is often great reluctance to administer systemic agents and/or radiotherapy to these patients given their susceptibility to DNA damage. The paucity of FA-HNSCC case reports limits evidence-based management, and such cases have not been analyzed collectively in detail. We present a systematic review of FA-HNSCC treatments reported from 1966 to 2020, defining a cohort of 119 patients with FA-HNSCC including 16 esophageal SCCs (131 total primary tumors), who were treated with surgery, radiotherapy, systemic therapy (including cytotoxic agents, EGFR inhibitors, or immune checkpoint inhibitors), or a combination of modalities. We summarize the clinical responses and regimen-associated toxicities by treatment modality. The collective evidence suggests that when possible, surgical resection with curative intent should remain the primary treatment modality for FA-HNSCC. Radiation can be administered with acceptable toxicity in the majority of cases, including patients who have undergone stem cell transplantation. Although there is little justification for cytotoxic chemotherapy, EGFR inhibitors and tyrosine kinase inhibitors may be both safe and effective. Immunotherapy may also be considered. Most oncologists have little personal experience with FA-HNSCC. This review is intended as a comprehensive resource for clinicians.

The factors that contribute to postoperative trismus after mandibulectomy and fibula free flap reconstruction (FFFR) are undefined. We retrospectively assessed postoperative trismus (defined as a maximum interincisal opening ≤35 mm) in 106 patients undergoing mandibulectomy with FFFR, employing logistic regression to identify risk factors associated with this sequela. The surgical indication was primary ablation in 64%, salvage for recurrence in 24%, and osteonecrosis in 12%. Forty-five percent of patients had existing preoperative trismus, and 58% of patients received adjuvant radiation/chemoradiation following surgery. The overall rates of postoperative trismus were 76% in the early postoperative period (≤3 months after surgery) and 67% in the late postoperative period (>6 months after surgery). Late postoperative trismus occurred more frequently in patients with ramus-involving vs. ramus-preserving posterior mandibulotomies (82% vs. 46%, p = 0.004). A ramus-involving mandibulotomy was the only variable significantly associated with trismus >6 months postoperatively on multivariable logistic regression (OR, 7.94; 95% CI, 1.85−33.97; p = 0.005). This work demonstrates that trismus is common after mandibulectomy and FFFR, and suggests that posterior mandibulotomies that involve or remove the ramus may predispose to a higher risk of persistent postoperative trismus.

There are currently no clinical strategies utilizing tumor gene expression to inform therapeutic selection for patients with head and neck squamous cell carcinoma (HNSCC). One of the challenges in developing predictive biomarkers is the limited characterization of preclinical HNSCC models. Patient-derived xenografts (PDXs) are increasingly recognized as translationally relevant preclinical avatars for human tumors; however, the overall transcriptomic concordance of HNSCC PDXs with primary human HNSCC is understudied, especially in human papillomavirus-associated (HPV+) disease. Here, we characterized 64 HNSCC PDXs (16 HPV+ and 48 HPV-) at the transcriptomic level using RNA-sequencing. The range of human-specific reads per PDX varied from 64.6%-96.5%, with a comparison of the most differentially expressed genes before and after removal of mouse transcripts revealing no significant benefit to filtering out mouse mRNA reads in this cohort. We demonstrate that four previously established HNSCC molecular subtypes found in The Cancer Genome Atlas (TCGA) are also clearly recapitulated in HNSCC PDXs. Unsupervised hierarchical clustering yielded a striking natural division of HNSCC PDXs by HPV status, with C19orf57 (BRME1), a gene previously correlated with positive response to cisplatin in cervical cancer, among the most significantly differentially expressed genes between HPV+ and HPV- PDXs. In vivo experiments demonstrated a possible relationship between increased C19orf57 expression and superior anti-tumor responses of PDXs to cisplatin, which should be investigated further. These findings highlight the value of PDXs as models for HPV+ and HPV- HNSCC, providing a resource for future discovery of predictive biomarkers to guide treatment selection in HNSCC.

Neural repair after stroke involves initiation of a cellular proliferative program in the form of angiogenesis, neurogenesis, and molecular growth signals in the surrounding tissue elements. This cellular environment constitutes a niche in which regeneration of new blood vessels and new neurons leads to partial tissue repair after stroke. Cancer metastasis has similar proliferative cellular events in the brain and other organs. Do cancer and CNS tissue repair share similar cellular processes? In this study, we identify a novel role of the regenerative neurovascular niche induced by stroke in promoting brain melanoma metastasis through enhancing cellular interactions with surrounding niche components. Repair-mediated neurovascular signaling induces metastatic cells to express genes crucial to metastasis. Mimicking stroke-like conditions in vitro displays an enhancement of metastatic migration potential and allows for the determination of cell-specific signals produced by the regenerative neurovascular niche. Comparative analysis of both in vitro and in vivo expression profiles reveals a major contribution of endothelial cells in mediating melanoma metastasis. These results point to a previously undiscovered role of the regenerative neurovascular niche in shaping the tumor microenvironment and brain metastatic landscape.

The epidermal growth factor receptor (EGFR) inhibitor cetuximab is the only FDA-approved oncogene-targeting therapy for head and neck squamous cell carcinoma (HNSCC). Despite variable treatment response, no biomarkers exist to stratify patients for cetuximab therapy in HNSCC. Here, we applied unbiased hierarchical clustering to reverse-phase protein array molecular profiles from patient-derived xenograft (PDX) tumors and revealed 2 PDX clusters defined by protein networks associated with EGFR inhibitor resistance. In vivo validation revealed unbiased clustering to classify PDX tumors according to cetuximab response with 88% accuracy. Next, a support vector machine classifier algorithm identified a minimalist biomarker signature consisting of 8 proteins - caveolin-1, Sox-2, AXL, STING, Brd4, claudin-7, connexin-43, and fibronectin - with expression that strongly predicted cetuximab response in PDXs using either protein or mRNA. A combination of caveolin-1 and Sox-2 protein levels was sufficient to maintain high predictive accuracy, which we validated in tumor samples from patients with HNSCC with known clinical response to cetuximab. These results support further investigation into the combined use of caveolin-1 and Sox-2 as predictive biomarkers for cetuximab response in the clinic.