Morris, John C.

Abstract Background: Viral vectors based on the Edmonston strain of measles virus (MV-Edm) selectively destroy all tumor cell lines tested in vitro. The oncolytic activity of the virus is enhanced by expression of the thyroidal sodium iodide symporter (MV-NIS) that allows selective 131I uptake by infected tumor cells and eliminates myeloma tumor xenografts that are resistant to the parent virus. MV-NIS is being considered for therapy of patients with relapsed or refractory multiple myeloma. Advanced myeloma is associated with significant immunosuppression with the potential risk of uncontrolled virus proliferation. The number of agents with activity against MV is limited. Low energy (Auger) electrons have a short path length and selectively damage cells in which the isotope decays. Thus, we hypothesized that the Auger electron emitting isotope 125I, selectively taken up by cells expressing NIS, can be used to control viral proliferation. Methods: A replication competent MV that expressed both a soluble form of carcinoembryonic antigen (CEA) and NIS (MV-NICE) was rescued and characterized. Cells were infected with MV-NICE or control vectors and exposed to 125I with appropriate controls. CEA expression and viral titers were determined at different time points. The role of free radical generation on virus replication was explored. In vivo control of MV-NICE replication with 125I was attempted. Results: MV-NICE replication in vitro is inhibited by the selective uptake of 125I by cells expressing NIS. Extracellular decay of the isotope has no effect on virus proliferation. Auger electron damage is in part mediated by free radicals and abrogated by glutathione. In myeloma xenografts, control of MV-NICE with 125I was not possible under the conditions of the experiment. Conclusion: MV-NICE does not replicate faster in the presence of radiation under our experimental conditions. Auger electron emitting isotopes effectively stop propagation of MV vectors expressing NIS in vitro. Additional work is necessary to translate these observations in vivo.

Abstract “I have noticed in operations of this kind, which I have seen performed by others upon the living, and in a number of excisions, which I have myself performed on the dead body, that most of the difficulty in the separation of the tumor has occurred in the region of these ligaments…. This difficulty, I believe, to be a very frequent source of that accident, which so commonly occurs in removal of goiter, I mean division of the recurrent laryngeal nerve.” Sir James Berry (1887)

We describe a family with multiple endocrine neoplasia type 2A (MEN2A) caused by the D631Y RET mutation resulting in an atypical phenotype. The index case was a 24-year-old man with history of recurrent anaplastic ependymoma incidentally found to have the D631Y RET mutation. At first assessment, four family members had evidence of large pheochromocytomas. One patient was found to have micromedullary thyroid cancer at 79 years of age. None of the patients had primary hyperparathyroidism. Patients with MEN2A caused by a D631Y RET mutation most commonly present with pheochromocytomas. Medullary thyroid cancer is a less common part of the syndrome when compared with other RET mutations.

Background: Medullary thyroid cancer, although most commonly sporadic, may be part of the multiple endocrine neoplasia type 2 (MEN2) syndromes, generally due to mutations in the RET proto-oncogene. The majority of these mutations are located in exons 10, 11, and 13–16. More rarely, mutations in other exons have been described. We report for the first time a family from the United States with a rare mutation involving exon 8 of the RET proto-oncogene, corresponding to a p.Gly533Cys substitution (G533C) leading to the development of MEN2A syndrome in several affected family members. This mutation had only been previously described in a large family in Brazil and in 7.75% of patients with apparently sporadic medullary thyroid cancer (MTC) in Greece. Methods: Given a strong index of suspicion, a genetic analysis to evaluate for uncommon mutations in the RET proto-oncogene identified the presence of the G533C missense mutation, despite initial negative screening for common mutations. We describe a family with a total of 47 individuals from five generations with multiple members affected with this mutation. Results: Our data suggest that in patients with this mutation, pheochromocytoma is more common than previously reported, and that in some cases this mutation may be associated with a more aggressive phenotype than initially described. Conclusions: MEN2A due to the G533C mutation in exon 8 may be more common and more aggressive than previously recognized. In patients with medullary thyroid cancer with negative screening for common mutations in the RET oncogene but a strong index of suspicion, DNA sequence analysis of less commonly involved exons should be considered.

The development of subspecialty tumor groups for uncommon malignancies represents an effective approach to building experience, increasing patient volumes and referrals, and fostering development of increased therapeutic options and clinical trials for patients afflicted with otherwise historically neglected cancers.