**1. Introduction**

314 Sex Steroids

van der Sluis IM., Boot AM., Krenning EP., Drop SLS., & de Muinck Keizer-Schrama SMPF.

agonist therapy. J Clin Endocrinol Metab 2Vol.87, No.2, pp. 506-512 Yamazaki K., Matsuoka H., Kawanobe S., Hujita Y., & Murata M. (1994). Evaluation of

data. J Jpn. Pediatr. Soc. Vol.98, pp. 96-102(in Japanese)

(2002). Longitudinal follow-up of bone density and body composition in children with precocious or early puberty before, during and after cessation of GnRH

standard body weight by sex, age, and height. On the basis of 1990 school year

Malignant salivary gland tumors (MSGTs) account for 2-6% of all head and neck cancers (Glisson et al., 2004; Milano et al., 2007). Despite their rarity, MSGTs have been of great interest because of their wide variety of pathological features and high rates of metastasis, which result in poor prognoses. Surgical resection followed by radiation therapy is the primary therapy for this malignancy. Adjuvant therapy is reserved for the management of local recurrence no longer amenable to additional local therapy and for metastasis. Based on studies of other types of tumors, particularly breast cancer, the expression and function of sex steroid hormone receptors in cancer have been extensively studied and the findings applied to diagnosis and treatment (Clarke & Sutherland, 1990; Kester et al., 1997). Although a number of studies have been published, the rationale for hormone therapy of MSGTs remains controversial because of disparate results and an insufficient number of cases. However, some recent studies have shown that certain salivary gland neoplasms are similar to breast cancer, not only in terms of their pathological features, but also at the molecular level (Pia-Foschini, 2003; Wick et al., 1998; Yoshimura et al., 2007). Here, we shed light on the biological similarity between MSGTs and certain types of breast cancer, and describe the potential use of hormone and additional therapies for MSGTs.
