To compare our data to MEN1 series in the literature, all causes of death were expressed as a percentage of the total deaths, as was done in most of these series (see Table 12). When expressed in this form, our data demonstrated the main single cause of death was due to PETs accounting for 38% (NIH) and 44% (pooled literature series) of the total deaths, followed by death from thymic carcinoid tumors (12%–13%). For 15 large series of MEN1 patients in the literature, the average percentage of death due to a PET-related illness was 53.1 ± 7% of all deaths; however, this percentage, as well as the exact causes of the PET-related death, varied widely in the individual series, with the total percentage varying from 19% of all deaths78,251 to 91% of all deaths.254 In the NIH and pooled literature series, the major cause of a PET-related death was the malignant nature of the PET, responsible for 36% of the total 44% PET-related deaths in the pooled literature series and for all 38% of the PET-related deaths in the NIH patients. In 14 of 15 of the large MEN1 literature series (see Table 12), PET-related illnesses were also the major cause of death (mean, 56% ± 7%); however, in 1 series251 the main cause of death was related to malignant thymic carcinoid tumors (24% of all deaths). Similar to our 2 groups of MEN1 patients (the NIH and pooled literature series), in 8 of the 14 literature MEN1 series where PET-related illnesses were the leading cause of death,57,78,88,129,150,217,378,379,448,465 the major cause of the PET-related death was the malignant nature of the PET, averaging 39% ± 9% of all deaths (range, 14%–83% of all deaths).