Drosophila hydei as a potential vector of Ceratocystis fimbriata, the causal agent of sweetpotato black rot, in storage facilities

Ceratocystis fimbriata, the causal agent of sweetpotato black rot, is a pathogen capable of developing and spreading within postharvest settings. A survey of North Carolina sweetpotato storage facilities was conducted to determine the arthropods present and identify potential vectors of C. fimbriata. Sixteen taxonomic categories were recovered and the genus Drosophila (Diptera: Drosophilidae) accounted for 79% of individuals sampled with Drosophila hydei (Sturtevant) being the most abundant species. Behavioral assays were conducted to determine if D. hydei is attracted to C. fimbriata inoculated roots and if the pathogen could be recovered from external or internal surfaces of the insect. Flies were released in insect trapping pitchers containing either C. fimbriata inoculated or non-inoculated roots or Petri dishes. No significant differences in fly number were detected in sweetpotato-baited pitchers; however, significant differences were found in the pitcher baited with a mature C. fimbriata culture. Flies were subjected to washes to determine if viable C. fimbriata was present (internally or externally); washes were plated onto carrot agar plates and observed for the presence of C. fimbriata colonies. Both external and internal washes had viable C. fimbriata inoculum with no significant differences, and inoculated sweetpotatoes had a significantly higher number of flies carrying C. fimbriata. This study suggests that D. hydei can carry C. fimbriata from infected sweetpotatoes and move viable C. fimbriata inoculum both externally and internally, making this the first report of any Drosophila spp. serving as a potential vector for the Ceratocystis genus.

Institutional variation in the thoroughness of pathologic assessment and pathologic complete response rates for locally advanced rectal cancers treated with neoadjuvant chemoradiation

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Background: A pathologic complete response (pCR) after neoadjuvant therapy and surgical excision is associated with a better prognosis and guides the management of patients with locally advanced rectal cancer. It is not known whether the thoroughness of pathologic assessment correlates with the finding of pCR. Methods: We introduce a surrogate measure for the thoroughness of pathologic assessment by taking the ratio of maximum residual tumor size and the number of cassettes prepared from the tumor: the Tumor Size to Cassette Ratio (TSCR). We retrospectively reviewed pathology reports from 259 patients with Stage II/III rectal cancer enrolled in a multicenter prospective clinical trial to determine whether TSCR is associated with pCR. Results: Of 247 included patients, 71 (29%) had a pCR. The pCR rate ranged from 0-45% and TSCR ranged from 0.0004 to 1.67 across the twelve trial sites. TSCR was significantly associated with pCR on univariable analysis. On multivariable analysis, TSCR remained significantly associated with pCR (odds ratio of 0.05; 95% CI 0.008-0.302) after adjusting for clinical stage, tumor size, distance from anal verge, radiation dose, and the number of neoadjuvant cycles of FOLFOX received. Conclusions: Pathologists tend to assess rectal cancer specimens with a pCR more thoroughly, but the thoroughness of pathologic assessment of residual tumor specimens varies between institutions. The thoroughness of pathologic assessment is associated with pCR. This raises the need for further standardization in the assessment of rectal cancer specimens after neoadjuvant chemoradiation.

Integrated genomic profiling identifies microRNA-92a regulation of IQGAP2 in locally advanced rectal cancer

Locally advanced rectal cancer (LARC) is treated with chemoradiation prior to surgical excision, leaving residual tumors altered or completely absent. Integrating layers of genomic profiling might identify regulatory pathways relevant to rectal tumorigenesis and inform therapeutic decisions and further research. We utilized formalin-fixed, paraffin-embedded pre-treatment LARC biopsies (n=138) and compared copy number, mRNA, and miRNA expression with matched normal rectal mucosa. An integrative model was used to predict regulatory interactions to explain gene expression changes. These predictions were evaluated in vitro using multiple colorectal cancer cell lines. The Cancer Genome Atlas (TCGA) was also used as an external cohort to validate our genomic profiling and predictions. We found differentially expressed mRNAs and miRNAs that characterize LARC. Our integrative model predicted the upregulation of miR-92a, miR-182, and miR-221 expression to be associated with downregulation of their target genes after adjusting for the effect of copy number alterations. Cell line studies using miR-92a mimics and inhibitors demonstrate that miR-92a expression regulates IQGAP2 expression. We show that endogenous miR-92a expression is inversely associated with endogenous KLF4 expression in multiple cell lines, and that this relationship is also present in rectal cancers of TCGA. Our integrative model predicted regulators of gene expression change in LARC using pre-treatment FFPE tissues. Our methodology implicated multiple regulatory interactions, some of which are corroborated by independent lines of study, while others indicate new opportunities for investigation.

KRAS and Combined KRAS/TP53 Mutations in Locally Advanced Rectal Cancer are Independently Associated with Decreased Response to Neoadjuvant Therapy

BACKGROUND

The response of rectal cancers to neoadjuvant chemoradiation (CRT) is variable, but tools to predict response remain lacking. We evaluated whether KRAS and TP53 mutations are associated with pathologic complete response (pCR) and lymph node metastasis after adjusting for neoadjuvant regimen.

METHODS

Retrospective analysis of 229 pretreatment biopsies from patients with stage II/III rectal cancer was performed. All patients received CRT. Patients received 0-8 cycles of FOLFOX either before or after CRT, but prior to surgical excision. A subset was analyzed to assess concordance between mutation calls by Sanger Sequencing and a next-generation assay.

RESULTS

A total of 96 tumors (42 %) had KRAS mutation, 150 had TP53 mutation (66 %), and 59 (26 %) had both. Following neoadjuvant therapy, 59 patients (26 %) achieved pCR. Of 133 KRAS wild-type tumors, 45 (34 %) had pCR, compared with 14 of 96 (15 %) KRAS mutant tumors (p = .001). KRAS mutation remained independently associated with a lower pCR rate on multivariable analysis after adjusting for clinical stage, CRT-to-surgery interval and cycles of FOLFOX (OR 0.34; 95 % CI 0.17-0.66, p < .01). Of 29 patients with KRAS G12V or G13D, only 2 (7 %) achieved pCR. Tumors with both KRAS and TP53 mutation were associated with lymph node metastasis. The concordance between platforms was high for KRAS (40 of 43, 93 %).

CONCLUSIONS

KRAS mutation is independently associated with a lower pCR rate in locally advanced rectal cancer after adjusting for variations in neoadjuvant regimen. Genomic data can potentially be used to select patients for "watch and wait" strategies.

Organ Preservation in Rectal Adenocarcinoma: a phase II randomized controlled trial evaluating 3-year disease-free survival in patients with locally advanced rectal cancer treated with chemoradiation plus induction or consolidation chemotherapy, and total mesorectal excision or nonoperative management

Background

Treatment of patients with non-metastatic, locally advanced rectal cancer (LARC) includes pre-operative chemoradiation, total mesorectal excision (TME) and post-operative adjuvant chemotherapy. This trimodality treatment provides local tumor control in most patients; but almost one-third ultimately die from distant metastasis. Most survivors experience significant impairment in quality of life (QoL), due primarily to removal of the rectum. A current challenge lies in identifying patients who could safely undergo rectal preservation without sacrificing survival benefit and QoL.

Methods/Design

This multi-institutional, phase II study investigates the efficacy of total neoadjuvant therapy (TNT) and selective non-operative management (NOM) in LARC. Patients with MRI-staged Stage II or III rectal cancer amenable to TME will be randomized to receive FOLFOX/CAPEOX: a) before induction neoadjuvant chemotherapy (INCT); or b) after consolidation neoadjuvant chemotherapy (CNCT), with 5-FU or capecitabine-based chemoradiation. Patients in both arms will be re-staged after completing all neoadjuvant therapy. Those with residual tumor at the primary site will undergo TME. Patients with clinical complete response (cCR) will receive non-operative management (NOM). NOM patients will be followed every 3 months for 2 years, and every 6 months thereafter. TME patients will be followed according to NCCN guidelines. All will be followed for at least 5 years from the date of surgery or—in patients treated with NOM—the last day of treatment.

Discussion

The studies published thus far on the safety of NOM in LARC have compared survival between select groups of patients with a cCR after NOM, to patients with a pathologic complete response (pCR) after TME. The current study compares 3-year disease-free survival (DFS) in an entire population of patients with LARC, including those with cCR and those with pCR. We will compare the two arms of the study with respect to organ preservation at 3 years, treatment compliance, adverse events and surgical complications. We will measure QoL in both groups. We will analyze molecular indications that may lead to more individually tailored treatments in the future. This will be the first NOM trial utilizing a regression schema for response assessment in a prospective fashion.

Trial registration

NCT02008656

Effect of adding mFOLFOX6 after neoadjuvant chemoradiation in locally advanced rectal cancer: a multicentre, phase 2 trial

BACKGROUND

Patients with locally advanced rectal cancer who achieve a pathological complete response to neoadjuvant chemoradiation have an improved prognosis. The need for surgery in these patients has been questioned, but the proportion of patients achieving a pathological complete response is small. We aimed to assess whether adding cycles of mFOLFOX6 between chemoradiation and surgery increased the proportion of patients achieving a pathological complete response.

METHODS

We did a phase 2, non-randomised trial consisting of four sequential study groups of patients with stage II-III locally advanced rectal cancer at 17 institutions in the USA and Canada. All patients received chemoradiation (fluorouracil 225 mg/m(2) per day by continuous infusion throughout radiotherapy, and 45·0 Gy in 25 fractions, 5 days per week for 5 weeks, followed by a minimum boost of 5·4 Gy). Patients in group 1 had total mesorectal excision 6-8 weeks after chemoradiation. Patients in groups 2-4 received two, four, or six cycles of mFOLFOX6, respectively, between chemoradiation and total mesorectal excision. Each cycle of mFOLFOX6 consisted of racemic leucovorin 200 mg/m(2) or 400 mg/m(2), according to the discretion of the treating investigator, oxaliplatin 85 mg/m(2) in a 2-h infusion, bolus fluorouracil 400 mg/m(2) on day 1, and a 46-h infusion of fluorouracil 2400 mg/m(2). The primary endpoint was the proportion of patients who achieved a pathological complete response, analysed by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00335816.

FINDINGS

Between March 24, 2004, and Nov 16, 2012, 292 patients were registered, 259 of whom (60 in group 1, 67 in group 2, 67 in group 3, and 65 in group 4) met criteria for analysis. 11 (18%, 95% CI 10-30) of 60 patients in group 1, 17 (25%, 16-37) of 67 in group 2, 20 (30%, 19-42) of 67 in group 3, and 25 (38%, 27-51) of 65 in group 4 achieved a pathological complete response (p=0·0036). Study group was independently associated with pathological complete response (group 4 compared with group 1 odds ratio 3·49, 95% CI 1·39-8·75; p=0·011). In group 2, two (3%) of 67 patients had grade 3 adverse events associated with the neoadjuvant administration of mFOLFOX6 and one (1%) had a grade 4 adverse event; in group 3, 12 (18%) of 67 patients had grade 3 adverse events; in group 4, 18 (28%) of 65 patients had grade 3 adverse events and five (8%) had grade 4 adverse events. The most common grade 3 or higher adverse events associated with the neoadjuvant administration of mFOLFOX6 across groups 2-4 were neutropenia (five in group 3 and six in group 4) and lymphopenia (three in group 3 and four in group 4). Across all study groups, 25 grade 3 or worse surgery-related complications occurred (ten in group 1, five in group 2, three in group 3, and seven in group 4); the most common were pelvic abscesses (seven patients) and anastomotic leaks (seven patients).

INTERPRETATION

Delivery of mFOLFOX6 after chemoradiation and before total mesorectal excision has the potential to increase the proportion of patients eligible for less invasive treatment strategies; this strategy is being tested in phase 3 clinical trials.

FUNDING

National Institutes of Health National Cancer Institute.

Marker detection in rectal cancer chemoradiation response using an exhaustive combinatorics approach

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Background: Our objective was to detect a set of markers that predicted tumor response to chemoradiationtherapy (CRT) in a prospective phase II protocol. Our hypothesis was that certain combinations of markers had a synergistic effect on those patients with a complete response (pCR) versus other responses. Methods: 132 rectal cancer patients’ tumors were evaluated for mutations and polymorphisms in 23 genes. The factors were selected prospectively as having the potential to influence CRT outcome. Our selected risk factors were transformed to yes/no values from predetermined cutoffs. We performed a massive computational combinatorics search for those combinations of factors associated with tumor response (3 million possible combinations). Our best sets of candidates were those with the largest association with tumor response to CRT (CR vs other) by Fisher’s Exacttests after adjusting for False Discovery Rate. Results: 33 of 132 (25%) patients achieved a pCR and 99 (75%) patients had non-pCR. Our results showed that sets of markers may work alone or synergistically. For example, some markers may not be associated with CRT response by themselves, but are highly correlated to outcome in the presence of other markers. Interactions such as we modeled here are often not considered by informatics software due to computational complexity. Conclusions: A combinatorics approach is computationally expensive but is able to detect marker combinations that are more complex (i.e., nonlinear) than those commonly used in popular informatics software. Our methods are readily extensible to any marker detection scenario, given sufficient computational resources. [Table: see text]

Gene expression profiles of rectal cancers with mutant or wild-type Kras

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Background: The Kras oncogene is one of the most common mutations in colorectal cancer. Kras mutations are associated with increased tumor aggressiveness, poor response to selected targeted therapies, and reduced patient survival. We have previously shown that rectal cancers carrying a Kras mutation were less likely to achieve a pathologic complete response to radiation compared to tumors with wild type Kras. Our objective was to compare the gene expression profiles of rectal cancers with mutant and wild type Kras to identify genes that could be related to the Kras–dependent aggressive phenotype. Methods: Pretreatment biopsy tissue was collected from 120 patients with stages I, II and III rectal cancer treated in two prospective trials (NCT00335816 and NCT00114231). DNA and total RNA were extracted from microdissected cancer cells. Mutations in codons 12, 13, and 61 of the Kras gene were detected by pCR. 50ng of total RNAs were amplified to generate cDNA libraries using Ovation FFPE WTA System (NuGEN Technologies, Inc., San Carlos, CA). The amplified cDNA was labeled using the Encore Biotin Module, and hybridized to GeneChip Human Genome U133A plus 2.0 arrays (Affymetrix, Inc., Cleveland, OH). Differences in gene expression between mutant and wild type Kras tumors were determined using T-test and Q-bound to correct for multiple testing by performing false discovery rate (FDR) analysis. Results: A total of 44 of 117 (37.6%) were mutant Kras. A total of 379 probes were upregulated and 262 were downregulated in tumors with Kras mutant compared to Kras wild type. Heatmap based on differentially expressed genes showed separation according to Kras mutant status. REG4 expression was increased 3 fold and CXCL5 was reduced 2.4 fold in tumors with mutant Kras compared to wild type Kras. The changes in expression on these genes are concordant with their known involvement in prognosis and response to therapy of colorectal cancer. Conclusions: The search for changes in gene expression in response to Kras activation led to identifying a number of genes associated with the tumor aggressive phenotype.

Mitogen-activated protein kinases are in vivo transducers of osmosensory signals in fish gill cells

The abundance and activity of three subgroups of mitogen-activated protein (MAP) kinases, the extracellular signal regulated kinase 1 (ERK1), stress-activated protein kinase 1/ Jun N-terminal kinase (SAPK1), and stress-activated protein kinase 2/ p38 (SAPK2), were measured in gill epithelium of the euryhaline teleost Fundulus heteroclitus exposed for 1 h to 4 weeks to hyper- and hyposmotic stress. The abundance of ERK1, SAPK1 and SAPK2 was analyzed by standard Western immunodetection. MAP kinase activity is a function of phosphorylation and was measured using phospho-specific and MAP kinase subgroup-specific antibodies. The abundance of the 63 kDa fish isoform of SAPK2 increases significantly during hyper- but not hyposmotic stress while ERK1 and SAPK1 protein levels remain unchanged during both types of osmotic stress. In contrast to this small effect of osmotic stress on MAP kinase abundance, the activity of all MAP kinases decreases significantly in response to hyperosmotic stress and increases significantly during hyposmotic stress. These results demonstrate for the first time that the activity of all major MAP kinases is osmoregulated in gill epithelium of euryhaline fish. Based on these results we conclude that MAP kinases are important components of salinity adaptation and participate in osmosensory signaling pathways in gill epithelium of euryhaline fishes.

High-frequency oscillatory ventilation: a nursing approach to bedside care

The introduction of high-frequency oscillatory ventilation (HFOV) to the intensive care nursery has stimulated us to develop infant care protocols for babies so treated. We identified specific areas unique to the SensorMedics HFOV and initiated nursing techniques to address each of the following areas: assessment, airway care, feedings, positioning, and safety. In summary, while on HFOV, an infant's assessment and care need not be minimized.