By helping to promote the future integration of genetic testing in health care delivery, including clinical decision making, the MVP is designed to contribute to the development of precision medicine.

Mucinous cystic neoplasms (MCNs) of the pancreas are uncommon tumors. The classification and biologic potential of these neoplasms remain the subject of controversy. Attempts to classify these tumors in a similar manner to ovarian MCNs remains controversial, as even histologically benign-appearing pancreatic MCNs metastasize and are lethal. One hundred thirty cases of MCNs were identified in the files of the Endocrine Pathology Tumor Registry of the Armed Forces Institute of Pathology from the years 1979 to 1993. The pathologic features, including hematoxylin and eosin staining, histochemistry, immunohistochemistry (IHC), cell cycle analysis, and K-ras oncogene determination were reviewed. These findings were correlated with the clinical follow-up obtained in all cases. There were 130 women, aged 20-95 years (mean age at the outset, 44.6 years). The patients had vague abdominal pain, fullness, or abdominal masses. More than 95% of the tumors were in the pancreatic tail or body and were predominantly multilocular. The tumors ranged in size from 1.5 to 36 cm in greatest dimension, with the average tumor measuring >10 cm. A spectrum of histomorphologic changes were present within the same case and from case to case. A single layer of bland-appearing, sialomucin-producing columnar epithelium lining the cyst wall would abruptly change to a complex papillary architecture, with and without cytologic atypia, and with and without stromal invasion. Ovarian-type stroma was a characteristic and requisite feature. Focal sclerotic hyalinization of the stroma was noted. This ovarian-type stroma reacted with vimentin, smooth muscle actin, progesterone, or estrogen receptors by IHC analysis. There was no specific or unique epithelial IHC. K-ras mutations by sequence analysis were wild type in all 52 cases tested. Ninety percent of patients were alive or had died without evidence of disease (average follow-up 9.5 years), irrespective of histologic appearance; 3.8% were alive with recurrent disease (average 10 years after diagnosis); and 6.2% died of disseminated disease (average 2.5 years from diagnosis). Irrespective of the histologic appearance of the epithelial component, with or without stromal invasion, pancreatic MCNs should all be considered as mucinous cystadenocarcinomas of low-grade malignant potential. Pancreatic MCNs cannot be reliably or reproducibly separated into benign, borderline, or malignant categories.

The 1918 to 1919 “Spanish” influenza pandemic virus killed up to 50 million people. We report here clinical, pathological, bacteriological, and virological findings in 68 fatal American influenza/pneumonia military patients dying between May and October of 1918, a period that includes ∼4 mo before the 1918 pandemic was recognized, and 2 mo (September–October 1918) during which it appeared and peaked. The lung tissues of 37 of these cases were positive for influenza viral antigens or viral RNA, including four from the prepandemic period (May–August). The prepandemic and pandemic peak cases were indistinguishable clinically and pathologically. All 68 cases had histological evidence of bacterial pneumonia, and 94% showed abundant bacteria on Gram stain. Sequence analysis of the viral hemagglutinin receptor-binding domain performed on RNA from 13 cases suggested a trend from a more “avian-like” viral receptor specificity with G222 in prepandemic cases to a more “human-like” specificity associated with D222 in pandemic peak cases. Viral antigen distribution in the respiratory tree, however, was not apparently different between prepandemic and pandemic peak cases, or between infections with viruses bearing different receptor-binding polymorphisms. The 1918 pandemic virus was circulating for at least 4 mo in the United States before it was recognized epidemiologically in September 1918. The causes of the unusually high mortality in the 1918 pandemic were not explained by the pathological and virological parameters examined. These findings have important implications for understanding the origins and evolution of pandemic influenza viruses.

Background: Adenosquamous carcinoma is a rare aggressive subtype of pancreatic adenocarcinoma. We describe the clinical, pathologic, and molecular characteristics of 25 of these lesions, the largest series to date. Methods: Twenty-five cases of adenosquamous carcinoma of the pancreas diagnosed between 1961 and 1994 were retrieved from the files of the Endocrine Registry of the Armed Forces Institute of Pathology. Histologic features were reviewed, histochemical, immunohistochemical, and molecular (k-ras) studies were performed, and patient follow-up was obtained. Results: The patients included 17 men and eight women, aged 28 to 82 years (mean, 65.4 y). The patients usually experienced weight loss (n ‫؍‬ 17) or painless jaundice (n ‫؍‬ 11), while also presenting with other abdominal symptoms. The tumors affected the head most frequently (n ‫؍‬ 17), followed by the tail (n ‫؍‬ 9) or body (n ‫؍‬ 4). Five cases involved more than one anatomic region of the pancreas. Microscopically, all tumors demonstrated dual differentiation toward adenocarcinoma and squamous cell carcinoma. All cases tested were immunoreactive with keratin (AE1:AE3 and CK1), whereas other keratin markers were variably expressed: CK5/6 (88%), CK7 (68%), Cam5.2 (41%), and CK20(26%). CA-19 -9 (84%) and CEA (74%) were positive in the majority of the cases. K-ras oncogene mutations were identified in seven of 13 cases. All patients died from their disease an average of 5.8

The Million Veteran Program (MVP), initiated by the Department of Veterans Affairs (VA), aims to collect biosamples with consent from at least one million veterans. Presently, blood samples have been collected from over 800,000 enrolled participants. The size and diversity of the MVP cohort, as well as the availability of extensive VA electronic health records, make it a promising resource for precision medicine. MVP is conducting array-based genotyping to provide a genome-wide scan of the entire cohort, in parallel with wholegenome sequencing, methylation, and other 'omics assays. Here, we present the design and performance of the MVP 1.0 custom Axiom array, which was designed and developed as a single assay to be used across the multi-ethnic MVP cohort. A unified genetic quality-control analysis was developed and conducted on an initial tranche of 485,856 individuals, leading to a high-quality dataset of 459,777 unique individuals. 668,418 genetic markers passed quality control and showed high-quality genotypes not only on common variants but also on rare variants. We confirmed that, with non-European individuals making up nearly 30%, MVP's substantial ancestral diversity surpasses that of other large biobanks. We also demonstrated the quality of the MVP dataset by replicating established genetic associations with height in European Americans and African Americans ancestries. This current dataset has been made available to approved MVP researchers for genome-wide association studies and other downstream analyses. Further data releases will be available for analysis as recruitment at the VA continues and the cohort expands both in size and diversity.