Molecular targets in squamous cell carcinoma of the head and neck

Worldwide more than a half million people develop Head and Neck cancer annually. Despite a significant decrease in smoking, about 40,000 new patients are diagnosed with carcinoma of the head and neck annually in the United States, and 11,000 of them succumb to their disease. More than 90% of these cancers are squamous cell carcinoma. The survival rates of patients with squamous cell carcinoma of the head and neck (SCCHN) have not improved significantly despite multimodality therapy including surgery, radiation therapy, and chemotherapy. Recently, molecular targeted agents have shown significant improvement in clinical outcomes in chronic myelogeneous leukemia with imatinib, breast cancer with trastuzumab, colon cancer with bevacizumab and cetuximab, and renal cell cancer with sorafenib and sunitinib. In SCCHN the epidermal growth factor receptor (EGFR) antibody cetuximab has shown promising results in a phase III trial in combination with radiation. How best to integrate these agents with the traditional treatment modalities of surgery, radiotherapy, and cytotoxic chemotherapy is of vital importance but has yet to be determined. This article will discuss the biology of molecular targeted agents as well as current clinical trials and future directions of these agents in SCCHN.

The role of taxanes and targeted therapies in locally advanced head and neck cancer

PURPOSE OF REVIEW

This review presents new data on the role of taxanes and targeted therapies in the management of squamous cell carcinoma of the head and neck.

RECENT FINDINGS

Taxane-containing triplets are clearly superior as an induction regimen in locally advanced squamous cell carcinoma of the head and neck when compared with cisplatin/5 fluorouracil which has been the standard for two decades. Preliminary data suggest that the addition of a taxane to cisplatin/5 fluorouracil as induction regimen followed by chemoradiation may be superior to chemoradiation alone. The addition of cetuximab to radiation prolongs locoregional control and survival without increasing mucositis. Areas of active investigation are the search for epidermal growth factor receptor mutations and the optimal way of integrating epidermal growth factor receptor-directed therapies into standard management. Meanwhile new targets are explored.

SUMMARY

Taxane/cisplatin/5 fluorouracil induction chemotherapy is clearly superior to cisplatin/5 fluorouracil. Epidermal growth factor receptor directed therapies can safely be combined with radiation and the combination shows encouraging results.

Frequent high-level expression of the immunotherapeutic target Ep-CAM in colon, stomach, prostate and lung cancers

Epithelial cell adhesion molecule (Ep-CAM; CD326) is used as a target by many immunotherapeutic approaches, but little data are available about Ep-CAM expression in major human malignancies with respect to level, frequency, tumour stage, grade, histologic tumour type and impact on survival. We analysed by immunohistochemical staining tissue microarrays with 4046 primary human carcinoma samples from colon, stomach, prostate and lung cancers for both frequency and intensity of Ep-CAM expression under highly standardised conditions. A total of 3360 samples were analysable. High-level Ep-CAM expression was observed in 97.7% (n=1186) of colon, 90.7% of gastric (n=473), and 87.2% of prostate cancers (n=414), and in 63.9% of lung cancers (n=1287). No detectable Ep-CAM staining was found with only 0.4% of colon, 2.5% of gastric, 1.9% of prostate cancers, and 13.5% of lung cancers. The only significant correlation of Ep-CAM expression with tumour grading was observed in colon cancer where high-level Ep-CAM expression on grade 3 tumours was down to 92.1% (P<0.0001). Adenosquamous and squamous carcinomas of the lung had a lower percentage of high-level Ep-CAM expression compared to adenocarcinomas with 35.4 and 53.6%, respectively, and with 45.5 and 17.3% of tumours being Ep-CAM negative. With the exception of moderately differentiated colon carcinoma, where patients not expressing Ep-CAM on their tumours showed an inferior survival (P=0.0014), correlation of Ep-CAM expression with survival did not reach statistical significance for any of the other cancer indications and subgroups. In conclusion, the data strongly support the notion that Ep-CAM is a prime target for immunotherapies in major human malignancies. This is because the most common human cancers show (i) a low frequency of Ep-CAM-negative tumours, (ii) a high frequency of Ep-CAM expression on cells of a given tumour, and (iii) for most cancers, an insignificant influence of tumour staging, grading and histology on Ep-CAM expression.