Abstract
Abstract Lacrimal gland adenoid cystic carcinoma (LGACC) is a rare but highly lethal indolent cancer originating in the cells of secretory glands, primarily of the head and neck. With the 10-year survival rate of 20%, the only life extending technique is to remove the eye and surrounding socket contents followed by extensive chemoradiation. Despite radical treatment, LGACC has a poorer prognosis than head and neck adenoid cystic carcinoma in part due to its propensity for perineural invasion (PNI) and intracranial spread. Analysis of LGACC tumors has revealed signatures enriched for pathways known to be involved in normal LG development, suggesting LGACC tumor cells re-engage or hijack developmental programs during its progression. This project sought to evaluate if developmental pathways involved in embryologic LG innervation were similarly recapitulated by LGACC tumors, and whether any of those markers could be correlated to perineural invasion phenotypes. We performed microarray analysis of embryonic and adult murine lacrimal glands and generated a differential expression signature associated with normal LG developmental pathways. Among other pathways, Notch and FGF signaling are significantly upregulated during LG organogenesis and our group and others have shown that activating mutations in these pathways are correlated with poor prognosis in LGACC. Interestingly, among the highest differentially expressed genes in the embryonic LG was the low-affinity nerve growth factor receptor (p75NTR). We thus subsequently evaluated the expression of p75NTR in LGACC tumors and its correlation to PNI. Our immunofluorescent imaging of histologically confirmed tumors with PNI demonstrated that p75NTR is highly correlated to cancer cells that have invaded the nerve. This correlation of p75NTR expression in nerve infiltrating LGACC cells can inform our investigation into the mechanisms for LGACC PNI and elucidate possible therapeutic targets to limit this aggressive manifestation in LGACC. Citation Format: Acadia H. Moeyersoms, Ryan A. Gallo, Madison Weiss, Michelle M. Maeng, David T. Tse, Daniel Pelaez. Expression of the low affinity neurotrophin receptor (p75NTR) correlates with perineural invasion in adenoid cystic carcinoma of the lacrimal gland [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2405.