[Survival analysis and immunohistochemical study of HER-2 and AR (androgen receptor) expression in salivary duct carcinoma]

Androgen Receptor Expression in Primary Nonsquamous Cell Rare-Variant Carcinomas of the Head and Neck

Objective

Androgen receptor (AR) is a diagnostic immunohistochemical marker for salivary gland duct carcinoma (SDC), but other nonsquamous cell head and neck carcinomas (NSCCs) may also express it. The aim of this preliminary study was to investigate the immunohistochemical expression of AR in rare head and neck NSCCs.

Study Design

Retrospective analysis of histologic records.

Setting

A large community hospital.

Subjects and Methods

Twenty-seven patients with NSCC were selected (21 men, 6 women; average age, 69 years). Exclusion criteria were histologically confirmed primary and metastatic head and neck squamous cell carcinomas and thyroid carcinomas. AR immunohistochemistry was done on formalin-fixed, paraffin-embedded tissue blocks.

Results

Variable AR expression was found in 5 of 27 (25%) cases of NSCC. All 7 patients with SDC showed intense and extensive positive immunoreactivity. Of 27 NSCC tumors, 15 (56%) had negative staining.

Conclusion

In the head and neck, expression of AR is not limited to SDCs; other NSCCs also express it. When surgery or radiotherapy is not appropriate for recurrent or metastatic head and neck NSCC, palliative chemotherapy offers poor results. Antiandrogen therapy is well tolerated and is much less toxic than chemotherapy. Since androgen deprivation therapy has been used against SDCs, this therapy may theoretically be used in a small subset of head and neck NSCCs.

Pathological response of salivary duct carcinoma to trastuzumab and docetaxel therapy

Salivary duct carcinoma (SDC) has a poor prognosis owing to the high incidence of distant metastasis. Approximately 40 % of SDCs are positive for human epidermal growth factor receptor 2 (HER2), suggesting that anti-HER2 therapy for cases with distant metastasis may be effective. However, the pathological response of SDC metastases to anti-HER2 therapy has not been reported. A 44-year-old man was diagnosed with HER2-positive SDC of the submandibular gland with multiple distant metastases. After six cycles of trastuzumab/docetaxel therapy, the patient achieved clinical partial response for the primary tumor and complete response for the neck and distant metastases. Subsequently, the patient underwent submandibular gland resection and neck dissection. On histopathological examination, very few viable cancer cells were identified in the resected primary tumor. Unfortunately, the patient died of multiple distant metastases 12 months after initial treatment. Trastuzumab/docetaxel therapy can elicit a clinical and pathological response in HER2-positive SDC.

Human Epidermal Growth Factor Receptor 2 (HER2/neu) in Salivary Gland Carcinomas: A Review of Literature

The aim of our study is to assess the relation of human epidermal growth factor receptor 2 or HER2/neu with the development of salivary gland carcinomas and use of Herceptin in the treatment of these cancers. A literature search was conducted using MEDLINE accessed via the National Library of Medicine PubMed interface searching for articles from 1994 up to 2014 relating to the existence of HER-2 protein and gene in salivary gland carcinomas and HER2/neu targeted therapy, written in English language. Almost all the studies in literature reported a frequent over expression and amplification of HER2/nue in salivary duct carcinomas (SDC) compared to other salivary gland cancers. Herceptin given as a monotherapy was not effective. The data on Herceptin combined chemotherapy are potentially promising but inadequate to evaluate drug activity, as patients also received a variety of cytotoxic agents. Therefore, Herceptin contribution to tumour response outcomes could not be precisely determined and the total number of cases is not sufficient. It is recommended that further work involves a large series of HER2/neu positive salivary gland cancers (randomized control trial) treated with chemotherapy with and without Herceptin. This might need multi-institutional cooperation.