Head and neck squamous cell carcinomas do not express EGFRvIII

EGFR R521K Polymorphism Is Not a Major Determinant of Clinical Cetuximab Resistance in Head and Neck Cancer

Background: Head and neck squamous cell carcinomas (HNSCCs) are among the most abundant malignancies worldwide. Patients with recurrent/metastatic disease undergo combination chemotherapy containing cetuximab, the monoclonal antibody used against the epidermal growth factor receptor (EGFR). Cetuximab augments the effect of chemotherapy; however, a significant number of patients show therapy resistance. The mechanism of resistance is yet to be unveiled, although extracellular alterations of the receptor have been reported, and their role in cetuximab failure has been proposed. Aims: Here, we investigate possible effects of the multi-exon deletion variant (EGFRvIII), and the single nucleotide polymorphism EGFR R521K on cetuximab efficacy. Results: Our results show that in HNSCC patients, the EGFRvIII allele frequency is under 1%; therefore, it cannot lead to common resistance. EGFR R521K, present in 42% of the patients, is investigated in vitro in four HNSCC cell lines (two wild-type and two heterozygous for EGFR R521K). While no direct effect is found to be related to the EGFR status, cells harboring R521K show a reduced sensitivity in ADCC experiments and in vivo xenograft experiments. However, this preclinical difference is not reflected in the progression-free or overall survival of HNSCC patients. Furthermore, NK cell and macrophage presence in tumors is not related to EGFR R521K. Discussion: Our results suggest that EGFR R521K, unlike reported previously, is unable to cause cetuximab resistance in HNSCC patients; therefore, its screening before therapy selection is not justifiable.

Prognostic and predictive value of EGFR in head and neck squamous cell carcinoma

EGFR is an extensively studied biomarker in head and neck squamous cell carcinoma (HNSCC). In this review, we discuss the prognostic and predictive role of EGFR in HNSCC, focusing on the different molecular alterations in specific treatment modalities such as radiotherapy alone (RT), combination of surgery, RT and chemotherapy (CT), EGFR inhibitors. We considered EGFR at different molecular levels: protein expression, protein activation, gene copy number, polymorphisms, mutation, EGFRvIII expression and EGFR ligand expression.

Considering RT alone, evidence supports the predictive and prognostic role of high EGFR expression only when evaluated by quantitative assays: this may help select the patients who can mostly benefit from accelerated treatment. Conversely, no predictive biomarkers are available when treatment is a combination of surgery, CT and RT. For this combined treatment, several studies indicate that EGFR expression represents a good prognostic parameter only when measured by a “quantitative” or at least semi-quantitative method. With respect to EGFR inhibitors, neither EGFR expression nor increased gene copy number represent prognostic/predictive factors.

If validated, nuclear EGFR, TGFα levels, EGFR phopshorylation and polymorphisms could represent additional prognostic factors in relation to combination of surgery, CT and RT, while EGFR polymorphisms and high amphiregulin levels could have prognostic value in patients treated with EGFR inhibitors.

FGFR Family Members Protein Expression as Prognostic Markers in Oral Cavity and Oropharyngeal Squamous Cell Carcinoma

Introduction

Fibroblast growth factor receptor family member proteins (FGFR1–4) have been identified as promising novel therapeutic targets and prognostic markers in a wide spectrum of solid tumors. The present study investigates the expression and prognostic value of four FGFR family member proteins in a large multicenter oral cavity squamous cell carcinoma (OCSCC) and oropharyngeal squamous cell carcinoma (OPSCC) cohort.

Methods

Protein expression of FGFR1–4 was determined by immunohistochemistry on tissue microarrays containing 951 formalin-fixed paraffin embedded OCSCC and OPSCC tissues from the University Medical Center Utrecht and University Medical Center Groningen. Protein expression was correlated to overall survival using Cox regression models, and bootstrapping was performed as internal validation.

Results

FGFR proteins were highly expressed in 39–64 % of OCSCC and 63–79 % of OPSCC. Seventy-three percent (299/412) of OCSCC and 85 % (305/357) of OPSCC highly co-expressed two or more FGFR family member proteins. FGFR1 protein was more frequently highly expressed in human papillomavirus (HPV)-negative OPSCC than HPV-positive OPSCC (82 vs. 65 %; p = 0.008). Furthermore, protein expression of FGFR family members was not related to overall survival in OCSCC or OPSCC (p > 0.05).

Conclusion

FGFR family members are frequently highly expressed in OCSCC and OPSCC. These FGFR family member proteins are therefore potential targets for novel therapies that are urgently required to improve survival of OCSCC and OPSCC patients.

Electronic supplementary material

The online version of this article (doi:10.1007/s40291-016-0204-5) contains supplementary material, which is available to authorized users.

Epidermal growth factor receptor variant III in head and neck squamous cell carcinoma is not relevant for targeted therapy and irradiation

BACKGROUND

The epidermal growth factor receptor (EGFR) is an important regulator of cell growth and survival, and is highly variable in tumor cells. The most prevalent variation of the EGFR extracellular domain is the EGFR variant III (EGFRvIII). Some studies imply that EGFRvIII may be responsible for the poor response to the monoclonal EGFR-antibody Cetuximab, used therapeutically in head and neck squamous cell carcinoma (HNSCC). Due to inconsistent data in the literature regarding EGFRvIII prevalence and clinical relevance in HNSCC, especially its predictive value, we examined EGFRvIII-transfected cell lines and patient tissue samples.

RESULTS

In contrast to other recent publications, we were able to demonstrate EGFRvIII expression in HNSCC. However, we noted that the different detection methods yielded inconsistent results. Furthermore, our EGFRvIII transfected and EGFR wild type cell lines exhibited similar characteristics and response rates in the performed in vitro experiments.

MATERIALS AND METHODS

We conducted various inhibition and combined irradiation experiments using three EGFRvIII-transfected cell lines. Moreover, a patient cohort of 149 cases consisting of formalin fixed and paraffin embedded (FFPE) and fresh-frozen specimens was assayed via reverse transcriptase PCR (rtPCR) with gel electrophoresis and sequencing for EGFRvIII prevalence. In the rtPCR assays, we used five previously published EGFRvIII primers and EGFRvIII-positive glioblastoma tissue as a positive control. In addition, immunohistochemical staining was conducted.

CONCLUSIONS

EGFRvIII can be detected in HNSCC patient samples. Nevertheless, the low prevalence and similar response rates to targeted drugs and irradiation in vitro cast doubt regarding the clinical relevance of EGFRvIII in HNSCC.

Current Role of Dacomitinib in Head and Neck Cancer

INTRODUCTION

Recurrent and/or metastatic head and neck squamous cell carcinoma (HNSCC) has a dismal prognosis. With the emergence of monoclonal antibodies and tyrosine kinase inhibitors (TKI) targeting the epidermal growth factor receptor (EGFR), several drugs were developed and tested in HNSCC. To date, the monoclonal antibody cetuximab is the only approved therapy for curative and recurrent/metastatic patients. Other EGFR-targeting drugs either failed in the clinical trials or are still in the early phases of drug development and research.

AREAS COVERED

In this article, previously published data and ongoing studies regarding dacomitinib, a second-generation irreversible TKI, for the treatment of HNSCC are presented and discussed.

EXPERT OPINION

The current body of evidence is not mature enough to indicate the use of dacomitinib for the treatment of HNSCC in curative or in recurrent/metastatic settings. Phase II data suggest the potential of improved outcome in selected recurrent/metastatic HNSCC based on several biomarkers, which need to be evaluated in randomized phase III trials. Meanwhile, an ongoing phase I study is investigating dacomitinib's optimal dosing combined with and without cisplatin in the curative concomitant chemoradiotherapy setting.