Galanin receptor subtypes 1 and 2 as therapeutic targets in head and neck squamous cell carcinoma.

IMPORTANCE OF THE FIELD: Despite advances in the therapeutic approaches for head and neck squamous cell carcinoma (HNSCC) at some sites, no substantial improvement in treatment efficacy and survival has occurred over the past several decades. Recent application of molecular biology has focused on the importance of galanin and its receptors as potential therapeutic targets for HNSCC. AREAS COVERED IN THIS REVIEW: Our aim is to examine galanin receptor 1 (GALR1) and galanin receptor 2 (GALR2) as HNSCC therapeutic targets and explore opportunities and strategies for making use of GALR1 and GALR2 signaling. WHAT THE READER WILL GAIN: This review provides recent data about galanin receptor signaling and function in various cell types, especially HNSCC. Signaling through GALR1 induces cell cycle arrest and suppresses proliferation in HNSCC. Similar to GALR1, GALR2 not only induces cell cycle arrest but also apoptosis, which was not observed with GALR1. TAKE HOME MESSAGES: GALR1 and GALR2 act as tumor suppressors in HNSCC, in a p53-independent manner. The current data suggest that GALR1 and GALR2 are potentially significant therapeutic targets and prognostic factors in HNSCC.