Integrated genome and transcriptome sequencing identifies a noncoding mutation in the genome replication factor DONSON as the cause of microcephaly-micromelia syndrome.

While next-generation sequencing has accelerated the discovery of human disease genes, progress has been largely limited to the "low hanging fruit" of mutations with obvious exonic coding or canonical splice site impact. In contrast, the lack of high-throughput, unbiased approaches for functional assessment of most noncoding variants has bottlenecked gene discovery. We report the integration of transcriptome sequencing (RNA-seq), which surveys all mRNAs to reveal functional impacts of variants at the transcription level, into the gene discovery framework for a unique human disease, microcephaly-micromelia syndrome (MMS). MMS is an autosomal recessive condition described thus far in only a single First Nations population and causes intrauterine growth restriction, severe microcephaly, craniofacial anomalies, skeletal dysplasia, and neonatal lethality. Linkage analysis of affected families, including a very large pedigree, identified a single locus on Chromosome 21 linked to the disease (LOD > 9). Comprehensive genome sequencing did not reveal any pathogenic coding or canonical splicing mutations within the linkage region but identified several nonconserved noncoding variants. RNA-seq analysis detected aberrant splicing in DONSON due to one of these noncoding variants, showing a causative role for DONSON disruption in MMS. We show that DONSON is expressed in progenitor cells of embryonic human brain and other proliferating tissues, is co-expressed with components of the DNA replication machinery, and that Donson is essential for early embryonic development in mice as well, suggesting an essential conserved role for DONSON in the cell cycle. Our results demonstrate the utility of integrating transcriptomics into the study of human genetic disease when DNA sequencing alone is not sufficient to reveal the underlying pathogenic mutation.

A review of duodenal metastases from squamous cell carcinoma of the cervix presenting as an upper gastrointestinal bleed.

Upper gastrointestinal bleeding due to duodenal metastases is extremely uncommon. Extra-pelvic spread of squamous cell carcinoma (SCC) of the cervix to the small bowel is rare with only 6 reported cases in the English literature since 1981(PubMed, Medline).We report the case of a 49-year-old woman who presented with upper-gastrointestinal bleeding two years after the diagnosis of SCC of the cervix. At esophagogastroduodenoscopy, there was a stricture in the second part of the duodenum which was biopsied for a suspected neoplastic lesion. Histologic and immunohistochemical examination showed a malignant lesion with characteristics identical to her original tumor in the cervix confirming the duodenal metastases.The clinical presentation of a 'malignant' upper-gastrointestinal bleed due to duodenal metastases from SCC of the cervix is unusual. Awareness of such infrequent patterns of metastases in cervical cancer confirmed by histopathological diagnosis is important for best practice therapeutic decisions in these patients.

Pulmonary lymphangitic carcinomatosis from squamous cell carcinoma of the cervix.

INTRODUCTION: Pulmonary metastasis presenting as lymphangitic carcinomatosis arising from squamous cell carcinoma (SCC) of the cervix is a rare event. Poorly represented in the literature, this event is associated with a) difficulty in accurate diagnosis, b) grave prognosis, and the c) lack of recognized predisposing risk factors. CASE REPORT: A 50 year-old female presented at our practice with a three-month history of a productive cough associated with dyspnoea and shortness of breath. A chest x-ray and computed tomography (CT) scan revealed multiple bilateral patchy areas with subsegmental atelectasis in both lungs which was investigated with a bronchoscopy, left thoracoscopy, and a left lung biopsy. Pathological examination of the wedge biopsy of the left upper lobe revealed neoplastic sheets of cell disturbed along the septal vessels, perivascular/peribronchial lymphatics, and the subpleural lymphatics. This lymphangitic carcinomatosis was confirmed to be metastatic from SCC of the cervix that had been diagnosed and treated two years ago. She was treated with systemic Carbo/Taxol chemotherapy and corticosteroids as a palliative measure. Despite temporary improvement, she died 13 months later. CONCLUSION: Pulmonary lymphangitic carcinomatosis is a rare manifestation of metastatic SCC of the cervix. As clinical presentations including radiographic imaging mimics other pulmonary entities, accurate diagnosis remains a challenge. Increased clinical awareness of such patterns of metastases in cervical cancer supported by accurate pathological diagnosis is imperative to guide appropriate therapy in these patients.

Malignant mixed Mullerian tumors of the uterus: histopathological evaluation of cell cycle and apoptotic regulatory proteins.

AIM: The aim of our study was to evaluate survival outcomes in malignant mixed Mullerian tumors (MMMT) of the uterus with respect to the role of cell cycle and apoptotic regulatory proteins in the carcinomatous and sarcomatous components. METHODS: 23 cases of uterine MMMT identified from the Saskatchewan Cancer Agency (1970-1999) were evaluated. Immunohistochemical expression of Bad, Mcl-1, bcl-x, bak, mdm2, bax, p16, p21, p53, p27, EMA, Bcl-2, Ki67 and PCNA was correlated with clinico-pathological data including survival outcomes. RESULTS: Histopathological examination confirmed malignant epithelial component with homologous (12 cases) and heterologous (11 cases) sarcomatous elements. P53 was strongly expressed (70-95%) in 15 cases and negative in 5 cases. The average survival in the p53+ve cases was 3.56 years as opposed to 8.94 years in p53-ve cases. Overexpression of p16 and Mcl-1 were observed in patients with longer survival outcomes (>2 years). P16 and p21 were overexpressed in the carcinomatous and sarcomatous elements respectively. Cyclin-D1 was focally expressed only in the carcinomatous elements. CONCLUSIONS: Our study supports that a) cell cycle and apoptotic regulatory protein dysregulation is an important pathway for tumorigenesis and b) p53 is an important immunoprognostic marker in MMMT of the uterus.