Lower gingival squamous cell carcinoma with brain metastasis during long-term cetuximab treatment: A case report

Complete response of recurrent oral squamous cell carcinoma treated with cetuximab in combination with radiotherapy: A case series

Salvage surgery for recurrent oral squamous cell carcinoma (OSCC) often leads to a poor quality of life (QOL). The present study described three cases that resulted in favorable locoregional control with cetuximab in combination with radiotherapy (Cmab + RT). Case 1 had regional recurrence of OSCC at the lower right mastoid area 4 months after primary surgery. Case 2 had regional recurrence of OSCC at the parotid area 7 months after primary surgery. Case 3 had local recurrence of OSCC at the masticatory muscle and Rouviere's lymph nodes 1 year and 3 months after primary surgery. In all cases, Cmab + RT was performed, and disease-free survival was confirmed 4 months, 2 years and 6 months, and 10 months after Cmab + RT, respectively. Immunohistochemically, all resected tumors had no expression of 110-kDa catalytic subunit of class IA phosphatidylinositol 3-kinase (PI3Kp110α). In conclusion, if salvage surgery for recurrent OSCC results in a significantly low QOL, then shifting to chemoradiotherapy may be appropriate as a treatment strategy. In addition, strong evidence indicated that PI3Kp110α expression is associated with Cmab therapy efficacy.

EGFR Mutations in Head and Neck Squamous Cell Carcinoma

EGFR is a prototypical receptor tyrosine kinase that is overexpressed in multiple cancers including head and neck squamous cell carcinoma (HNSCC). The standard of care for HNSCC remains largely unchanged despite decades of research. While EGFR blockade is an attractive target in HNSCC patients and anti-EGFR strategies including monoclonal antibodies and kinase inhibitors have shown some clinical benefit, efficacy is often due to the eventual development of resistance. In this review, we discuss how the acquisition of mutations in various domains of the EGFR gene not only alter drug binding dynamics giving rise to resistance, but also how mutations can impact radiation response and overall survival in HNSCC patients. A better understanding of the EGFR mutational landscape and its dynamic effects on treatment resistance hold the potential to better stratify patients for targeted therapies in order to maximize therapeutic benefits.

Selective inhibition of PI3K110α as a novel therapeutic strategy for cetuximab‑resistant oral squamous cell carcinoma

High expression of the 110 kDa catalytic subunit of the class IA PI3K (PI3Kp110α) may play an important role in cetuximab resistance exhibited by both colorectal cancer and head and neck squamous cell carcinoma. Therefore, the present study aimed to examine the association between the expression of proteins in the PI3Kp110α pathway and cetuximab resistance, and the antitumor effects of alpelisib (PI3K inhibitor) and cetuximab in oral squamous cell carcinoma (OSCC) cells. The association between PI3Kp110α protein expression levels and the tumor response to cetuximab was determined using immunohistochemistry. OSCC cells were treated with alpelisib, cetuximab, or in combination, and the effects were examined in vitro and in vivo. PI3Kp110α protein expression was significantly associated with the tumor response to cetuximab (P<0.05) and 1-year progression-free survival and overall survival (P<0.05). Combined treatment of alpelisib and cetuximab resulted in enhanced antitumor effects in vitro compared with either agent administered alone. In particular, the expression level of N-cadherin, an epithelial-mesenchymal transition-related protein, was decreased, suggesting that the invasion potential of cetuximab-resistant cells decreased. Furthermore, the expression of proteins in the PI3K pathway were decreased in tumors from mice with OSCC xenografts treated with alpelisib and cetuximab in combination. These results indicate that novel regimens of systemic therapy (such as chemotherapy), with combinations of cetuximab and alpelisib, may be beneficial for patients with cetuximab-resistant OSCC.