Khush K, et al. J Heart Lung Transplant 2020.
PURPOSE: Gene expression profile (GEP) monitoring by AlloMap® is ISHLT-guideline recommended for graft surveillance after heart transplant (HT). The Outcomes in AlloMap Registry (OAR) is an observational, prospective study of HT patients monitored by AlloMap. The effect of malignancy on AlloMap scores is not well characterized. The large cohort of OAR patients with clinical data associated with AlloMap scores permits this characterization.
METHODS: Patients enrolled in the OAR study and >6 months post-HT were assessed for malignancy status and stratified by HT recipients with malignancy and those without. The malignancy groups were further stratified by non-skin cancers and skin cancers, where mean AlloMap scores were compared between groups.
RESULTS: 135 patients in the OAR registry (1.4%) with de-novo malignancy (including skin cancer) and 9395 patients with no de-novo malignancy >6 months post-HT and associated AlloMap scores were identified. Mean AlloMap score in patients with malignancy was significantly higher than in patients without malignancy (30.9 vs 30.1; p=0.0354) (Table 1). For HT patients with skin cancer vs no malignancy, there was not a statistically significant difference between GEP scores (30.7 vs 30.1; p=0.1390).
CONCLUSION: AlloMap scores were higher in HT recipients with any malignancy compared to HT patients without malignancy; however, scores were not statistically significant when looking only at skin-cancer versus no malignancy. Although statistically significant, the absolute difference was only small and therefore unlikely to have clinical impact. The GEP score comprises changes in gene expression in peripheral blood mononuclear cells (PBMCs). Recently, malignancy has been shown to cause changes
in gene expression in PBMCs, which may explain this observed difference. Further studies are warranted to replicate these findings and to determine whether cancer development causes an elevated AlloMap score.