Abstract There are approximately 47,000 new cases of head and neck cancer diagnosed in the United States each year. The survival rate has not improved significantly in the past 30 years. The development of new therapies for HNSCC and the understanding of its biology both depend upon clinically relevant animal models. There are several existing animal models for HNSCC that include chemically-induced cancer models, syngeneic models using animal cancer cells, transgenic mice, and xenograft models using cultured human HNSCC cell lines injected into immunocompromised mice, either subcutaneously or orthotopically. An increasingly promising xenograft model, the heterotransplant model, is developed by surgically implanting tumor tissue directly from a patient into an immunocompromised mouse. The resulting tumor is serially passaged in vivo and never cultured on plastic. We have transplanted 20 HNSCC primary tumors from untreated patients directly into mice that included 17 tongue tumors, one maxillary gingival tumor, and two from the floor of the mouth. Although several tumors grew initially in mice, only 2 of 20 (10%) established tumors that could be serially passaged and used for therapeutic and mechanistic studies. One cell line has been established from a tongue heterotransplant (HOSC1). The two established heterotransplants maintained the histological appearance of the original tumors. To test the biological and molecular signaling response of HNSCC to targeted therapy, we utilized one heterotransplant that was passaged into 40 mice. Both the Src inhibitor dasatinib and the JAK inhibitor INCB16562 modestly inhibited tumor growth; the combination was significantly more effective than the single agents. Likewise, the tumors treated with the combination had significantly more apoptosis and less proliferation than control tumors. Consistent with our published in vitro results, Src inhibition did not result in STAT3 inhibition, but JAK inhibition abrogated STAT3 activation. Src was inhibited in vivo by dasatinib. Our results demonstrate that the heterotransplant model of HNSCC has promise as an in vivo model to test the efficacy of anti-cancer drugs. The low “take rate” is problematic but will be addressed in the future by intra-operative biopsies and larger tumor specimens. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2361. doi:1538-7445.AM2012-2361