Prospective Statewide Study of Universal Screening for Hereditary Colorectal Cancer: The Ohio Colorectal Cancer Prevention Initiative.

Hereditary cancer syndromes infer high cancer risks and require intensive surveillance. Identification of high-risk individuals among patients with colorectal cancer (CRC) needs improvement. METHODS: Three thousand three hundred ten unselected adults who underwent surgical resection for primary invasive CRC were prospectively accrued from 51 hospitals across Ohio between January 1, 2013, and December 31, 2016. Universal Tumor screening (UTS) for mismatch repair (MMR) deficiency was performed for all, and pathogenic germline variants (PGVs) were identified using multigene panel testing (MGPT) in those who met at least one inclusion criterion: MMR deficiency, diagnosed < 50 years, multiple primary tumors (CRC or endometrial cancer), or with a first-degree relative with CRC or endometrial cancer. RESULTS: Five hundred twenty-five patients (15.9%) had MMR deficiency. Two hundred thirty-four of 3,310 (7.1%; 16% of the 1,462 who received MGPT) had 248 PGVs in cancer susceptibility genes. One hundred forty-two (4.3%) had a PGV in an MMR gene, and 101 (3.1%) had a PGV in a non-MMR gene. Ten with Lynch syndrome (LS) also had a non-MMR PGV and were included in both groups. Two (0.06%) had constitutional MLH1 hypermethylation. Of unexplained MMR-deficient patients, 88.4% (76 of 86) had double somatic MMR mutations. Testing for only MMR genes in MMR-deficient patients would have missed 18 non-MMR gene PGVs (7.3% of total PGVs identified). Had UTS been the only method used to screen for hereditary cancer syndromes, 38.6% (91 of 236) would have been missed, including 6.3% (9 of 144) of those with LS. These results have treatment implications as 5.3% (175 of 3,310) had PGVs in genes with therapeutic targets. CONCLUSION: UTS alone is insufficient for identifying a large proportion of CRC patients with hereditary syndromes, including some with LS. At a minimum, 7.1% of individuals with CRC have a PGV and pan-cancer MGPT should be considered for all patients with CRC.

Cancer cachexia is regulated by selective targeting of skeletal muscle gene products.

Cachexia is a syndrome characterized by wasting of skeletal muscle and contributes to nearly one-third of all cancer deaths. Cytokines and tumor factors mediate wasting by suppressing muscle gene products, but exactly which products are targeted by these cachectic factors is not well understood. Because of their functional relevance to muscle architecture, such targets are presumed to represent myofibrillar proteins, but whether these proteins are regulated in a general or a selective manner is also unclear. Here we demonstrate, using in vitro and in vivo models of muscle wasting, that cachectic factors are remarkably selective in targeting myosin heavy chain. In myotubes and mouse muscles, TNF-alpha plus IFN-gamma strongly reduced myosin expression through an RNA-dependent mechanism. Likewise, colon-26 tumors in mice caused the selective reduction of this myofibrillar protein, and this reduction correlated with wasting. Under these conditions, however, loss of myosin was associated with the ubiquitin-dependent proteasome pathway, which suggests that mechanisms used to regulate the expression of muscle proteins may be cachectic factor specific. These results shed new light on cancer cachexia by revealing that wasting does not result from a general downregulation of muscle proteins but rather is highly selective as to which proteins are targeted during the wasting state.

Prevalence and Spectrum of Germline Cancer Susceptibility Gene Mutations Among Patients With Early-Onset Colorectal Cancer.

IMPORTANCE: Hereditary cancer syndromes infer high cancer risks and require intensive cancer surveillance, yet the prevalence and spectrum of these conditions among unselected patients with early-onset colorectal cancer (CRC) is largely undetermined. OBJECTIVE: To determine the frequency and spectrum of cancer susceptibility gene mutations among patients with early-onset CRC. DESIGN, SETTING, AND PARTICIPANTS: Overall, 450 patients diagnosed with colorectal cancer younger than 50 years were prospectively accrued from 51 hospitals into the Ohio Colorectal Cancer Prevention Initiative from January 1, 2013, to June 20, 2016. Mismatch repair (MMR) deficiency was determined by microsatellite instability and/or immunohistochemistry. Germline DNA was tested for mutations in 25 cancer susceptibility genes using next-generation sequencing. MAIN OUTCOMES AND MEASURES: Mutation prevalence and spectrum in patients with early-onset CRC was determined. Clinical characteristics were assessed by mutation status. RESULTS: In total 450 patients younger than 50 years were included in the study, and 75 gene mutations were found in 72 patients (16%). Forty-eight patients (10.7%) had MMR-deficient tumors, and 40 patients (83.3%) had at least 1 gene mutation: 37 had Lynch syndrome (13, MLH1 [including one with constitutional MLH1 methylation]; 16, MSH2; 1, MSH2/monoallelic MUTYH; 2, MSH6; 5, PMS2); 1 patient had the APC c.3920T>A, p.I1307K mutation and a PMS2 variant; 9 patients (18.8%) had double somatic MMR mutations (including 2 with germline biallelic MUTYH mutations); and 1 patient had somatic MLH1 methylation. Four hundred two patients (89.3%) had MMR-proficient tumors, and 32 patients (8%) had at least 1 gene mutation: 9 had mutations in high-penetrance CRC genes (5, APC; 1, APC/PMS2; 2, biallelic MUTYH; 1, SMAD4); 13 patients had mutations in high- or moderate-penetrance genes not traditionally associated with CRC (3, ATM; 1, ATM/CHEK2; 2, BRCA1; 4, BRCA2; 1, CDKN2A; 2, PALB2); 10 patients had mutations in low-penetrance CRC genes (3, APC c.3920T>A, p.I1307K; 7, monoallelic MUTYH). Importantly, 24 of 72 patients (33.3%) who were mutation positive did not meet established genetic testing criteria for the gene(s) in which they had a mutation. CONCLUSIONS AND RELEVANCE: Of 450 patients with early-onset CRC, 72 (16%) had gene mutations. Given the high frequency and wide spectrum of mutations, genetic counseling and testing with a multigene panel could be considered for all patients with early-onset CRC.

The microphthalmia transcription factor and the related helix-loop-helix zipper factors TFE-3 and TFE-C collaborate to activate the tartrate-resistant acid phosphatase promoter.

The microphthalmia transcription factor (MITF) regulates different target genes in several distinct cell types, including osteoclasts. The role of the closely related factors TFE3 and TFEC in MITF action was studied. The TFE3 and TFEC proteins were expressed in osteoclast-like cells, and both could be immunoprecipitated in a complex with MITF. In transient transfection assays, TFE3 and TFEC could collaborate with MITF to superactivate the tartrate resistant acid phosphatase (TRAP) promoter, a target for MITF in osteoclasts. Although TFEC had been thought to act as a repressor, we could demonstrate that TFEC acted as a transactivator when fused to the gal4 DNA-binding domain in a yeast one-hybrid-type assay. Additionally, two mRNA isoforms of MITF, MITF-M and MITF-A, were detected in primary osteoclast-like cells by RT-PCR. In transient transfection assays, the MITF-A and MITF-M isoforms activated the promoter of the TRAP gene to the same extent, and both forms could collaborate equally well with TFE3 to activate the TRAP promoter. These results indicate that although different isoforms of MITF appear to be functionally similar, the TFE3 and TFEC proteins may collaborate with MITF to efficiently regulate expression of target genes in osteoclasts.

Capillary electrophoresis as a probe of enantiospecific interactions between photoactive transition metal complexes and DNA.

Recently, we have demonstrated the capacity to separate chiral transition metal (TM) complexes of the type [M(diimine)(3)](n+) using CE buffers containing chiral tartrate salts. In separate work, several chromium(III)-tris-diimine complexes in particular have been shown to bind enantioselectively with calf-thymus (CT) DNA, and a qualitative assessment of the relative strength and enantiospecificity of this interaction is of significant interest in the characterization of these complexes as potential DNA photocleavage agents. Here, we describe two convenient approaches to investigate such binding behavior using chiral CE. For complexes with lower DNA affinities exhibiting primarily surface binding, DNA itself is used as the chiral resolving agent in the electrophoretic buffer. In this approach, resolution of the TM complexes into their Lambda and Delta isomers is achieved with the isomer eluting later exhibiting superior binding affinity toward DNA. For more strongly bound TM complexes containing ligands known to intercalate with DNA, the [Cr(diimine)(3)](3+) complexes are preincubated with oligonucleotide and subsequently enantiomerically resolved in a dibenzoyl-L-tartrate buffer system that facilitates analysis of the unbound TM species only. Differences in isomer binding affinity are distinguished by the relative peak areas of the Lambda- and Delta-isomers, and relative binding strengths of different complexes can be inferred from comparison of the total amount of unbound complex at equivalent DNA/TM ratios.