Immunodepletion plasma proteomics by tripleTOF 5600 and Orbitrap elite/LTQ-Orbitrap Velos/Q exactive mass spectrometers.

Plasma proteomic experiments performed rapidly and economically using several of the latest high-resolution mass spectrometers were compared. Four quantitative hyperfractionated plasma proteomics experiments were analyzed in replicates by two AB SCIEX TripleTOF 5600 and three Thermo Scientific Orbitrap (Elite/LTQ-Orbitrap Velos/Q Exactive) instruments. Each experiment compared two iTRAQ isobaric-labeled immunodepleted plasma proteomes, provided as 30 labeled peptide fractions, and 480 LC-MS/MS runs delivered >250 GB of data in 2 months. Several analysis algorithms were compared. At 1% false discovery rate, the relative comparative findings concluded that the Thermo Scientific Q Exactive Mass Spectrometer resulted in the highest number of identified proteins and unique sequences with iTRAQ quantitation. The confidence of iTRAQ fold-change for each protein is dependent on the overall ion statistics (Mascot Protein Score) attainable by each instrument. The benchmarking also suggested how to further improve the mass spectrometry parameters and HPLC conditions. Our findings highlight the special challenges presented by the low abundance peptide ions of iTRAQ plasma proteome because the dynamic range of plasma protein abundance is uniquely high compared with cell lysates, necessitating high instrument sensitivity.

Immunohistochemistry staining for the mismatch repair proteins in the clinical care of patients with colorectal cancer.

PURPOSE: The Ohio State University was one of the first medical centers to begin routinely performing immunohistochemical staining for the four mismatch repair proteins (MLH1, MSH2, MSH6, and PMS2) on all newly diagnosed patients with colorectal cancer. The results of implementing this testing on a clinical basis are critically assessed. METHODS: From March 1, 2006, to March 31, 2008, 270 newly diagnosed colorectal cancer tumors received immunohistochemical staining for MLH1, MSH2, MSH6, and PMS2. If any stain was absent, the cancer genetic counselors were alerted, so that they could contact the patient. A follow-up genetic consultation was recommended for all patients with any stain absent other than MLH1 and to patients with absence of MLH1 +/- PMS2 who were diagnosed younger than 60 years had a multiple Lynch syndrome-associated cancers or had a first-degree relative with colorectal cancer or endometrial cancer. Those attending the genetic consultation were offered appropriate follow-up testing. RESULTS: There were 57 (21.1%) cases with abnormal immunohistochemical results. Genetics was able to contact 54 (94.7%) of these patients. It was determined that 34 (62.9%) of these 54 patients should be referred for a cancer genetics consultation, however, only nine (26.5%) made an appointment. Seven of the nine underwent additional testing, which was informative in five of the patients. Two (0.7%) new cases of Lynch syndrome were diagnosed and three patients were found to have proven/probable MLH1 promoter methylation. CONCLUSIONS: Routine immunohistochemical of the mismatch repair proteins on all newly diagnosed patients with colorectal cancer can be implemented clinically, however, patient uptake of follow-up genetic consultation is lower than expected.

Yttrium-90 microsphere induced gastrointestinal tract ulceration.

BACKGROUND: Radiomicrosphere therapy (RT) utilizing yttrium-90 (90Y) microspheres has been shown to be an effective regional treatment for primary and secondary hepatic malignancies. We sought to determine a large academic institution's experience regarding the extent and frequency of gastrointestinal complications. METHODS: Between 2004 and 2007, 27 patients underwent RT for primary or secondary hepatic malignancies. Charts were subsequently reviewed to determine the incidence and severity of GI ulceration. RESULTS: Three patients presented with gastrointestinal bleeding and underwent upper endoscopy. Review of the pretreatment angiograms showed normal vascular anatomy in one patient, sclerosed hepatic vasculature in a patient who had undergone prior chemoembolization in a second, and an aberrant left hepatic artery in a third. None had undergone prophylactic gastroduodenal artery embolization. Endoscopic findings included erythema, mucosal erosions, and large gastric ulcers. Microspheres were visible on endoscopic biopsy. In two patients, gastric ulcers were persistent at the time of repeat endoscopy 1-4 months later despite proton pump inhibitor therapy. One elderly patient who refused surgical intervention died from recurrent hemorrhage. CONCLUSION: Gastrointestinal ulceration is a known yet rarely reported complication of 90Y microsphere embolization with potentially life-threatening consequences. Once diagnosed, refractory ulcers should be considered for aggressive surgical management.

The frequency of Muir-Torre syndrome among Lynch syndrome families.

Lynch syndrome is the predisposition to visceral malignancies that are associated with deleterious germline mutations in DNA mismatch repair genes, including MLH1, MSH2, MSH6, and PMS2. Muir-Torre syndrome is a variant of Lynch syndrome that includes a predisposition to certain skin tumors. We determined the frequency of Muir-Torre syndrome among 50 Lynch syndrome families that were ascertained from a population-based series of cancer patients who were newly diagnosed with colorectal or endometrial carcinoma. Histories of Muir-Torre syndrome-associated skin tumors were documented during counseling of family members. Muir-Torre syndrome was observed in 14 (28%) of 50 families and in 14 (9.2%) of 152 individuals with Lynch syndrome. Four (44%) of nine families with MLH1 mutations had a member with Muir-Torre syndrome compared with 10 (42%) of 24 families with MSH2 mutations (P = .302). Families who carried the c.942+3A>T MSH2 gene mutation had a higher frequency of Muir-Torre syndrome than families who carried other mutations in the MSH2 gene (75% vs 25%; P = .026). Muir-Torre syndrome was not found in families with mutations in the MSH6 or PMS2 genes. Our results suggest that Muir-Torre syndrome is simply a variant of Lynch syndrome. Screening for Muir-Torre syndrome-associated skin lesions among patients with Lynch syndrome is recommended.