Comprehensive molecular pathology analysis of small bowel adenocarcinoma reveals novel targets with potential for clinical utility

Small bowel accounts for only 0.5% of cancer cases in the US but incidence rates have been rising at 2.4% per year over the past decade. One-third of these are adenocarcinomas but little is known about their molecular pathology and no molecular markers are available for clinical use.

Using a retrospective 28 patient matched normal-tumor cohort, next-generation sequencing, gene expression arrays and CpG methylation arrays were used for molecular profiling.

Next-generation sequencing identified novel mutations in IDH1, CDH1, KIT, FGFR2, FLT3, NPM1, PTEN, MET, AKT1, RET, NOTCH1 and ERBB4. Array data revealed 17% of CpGs and 5% of RNA transcripts assayed to be differentially methylated and expressed respectively (p < 0.01). Merging gene expression and DNA methylation data revealed CHN2 as consistently hypermethylated and downregulated in this disease (Spearman −0.71, p < 0.001). Mutations in TP53 which were found in more than half of the cohort (15/28) and Kazald1 hypomethylation were both were indicative of poor survival (p = 0.03, HR = 3.2 and p = 0.01, HR = 4.9 respectively).

By integrating high-throughput mutational, gene expression and DNA methylation data, this study reveals for the first time the distinct molecular profile of small bowel adenocarcinoma and highlights potential clinically exploitable markers.

Abstract 4792: Comprehensive molecular pathology analysis of small bowel adenocarcinoma reveals novel targets with clinical utility

Small bowel accounts for only 0.5% of cancer cases in the US; a third of which are adenocarcinomas. But incidence rates have been rising at a rate of 2.4% per year over the last decade. Because of the rarity of this cancer, little is known about its molecular pathology and there are no molecular markers for diagnosis, predicting prognosis or therapeutic intervention. The aim of this study was therefore to look into this disease at a molecular level to better understand its biology and identify biomarkers and potential points of therapeutic intervention.

Using a retrospective 28 patient matched normal-tumor cohort next generation sequencing (NGS) was performed using a 50 gene cancer hotspot panel, gene expression arrays were used to profile ∼29,000 RNA transcripts and 450k CpG methylation arrays were used to carry out DNA methylation analysis. We also looked at microsatellite instability (MSI), HER2 and p53 expression.

NGS identified novel mutations in IDH1, CDH1, KIT, NRAS, FGFR2, FLT3, NPM1, PTEN, MET, AKT1, RET, NOTCH1 and ERBB4. Previously known mutations such as high-frequency KRAS and TP53 and low-frequency HER2 were also confirmed in our cohort. The average patient had 2.6 mutations with eight patients having only a single mutation to one having seven. Array data revealed 17% of CpGs and 5% of RNA transcripts assayed to be differentially methylated and expressed respectively (p&lt;0.01). Gene expression and DNA methylation data was merged to reveal 266 transcripts where DNA methylation was inversely correlated with gene expression (Spearman &lt; -0.5). Almost 90% of these CpGs were found to be located inside gene bodies, the first exons and 5′ and 3′ UTRs. Almost 60% of the overall genome-wide changes in methylation (hyper and hypo) also occurred inside the gene bodies, the first exons and 5′ and 3′ UTRs. CHN2 was identified as one of the genes consistently hypermethylated and downregulated in tumor compared to normal (Spearman -0.71, p&lt;0.001). This trend was validated using immunohistochemistry and pyrosequencing. Finally mutations in TP53 which were found in more than half of the cohort (15/28) and Kazald1 hypomethylation were both were indicative of poor survival (p = 0.0345, HR = 3.2 and p = 0.0079, HR = 4.9 respectively). Sanger sequencing was used to confirm TP53 mutations and immunohistochemistry analysis confirmed protein overexpression in all mutant cases. Six cases were positive for MSI and three for HER2 overexpression.

This study has for the first time highlighted the extent of molecular changes taking place in SBA. The clinical potential of TP53 mutations and Kazald1 hypomethylation as prognostic biomarkers and CHN2 as a diagnostic biomarker are focus areas for further research by our group.

Citation Format: Muhammad A. Alvi, Darragh G. McArt, Paul Kelly, Marc-Aurel Fuchs, Matthew Alderdice, Clare M. McCabe, Victoria Bingham, Claire McGready, Stephen McQuaid, Perry Maxwell, Peter Hamilton, Jacqueline A. James, Richard Wilson, Manuel Salto-Tellez. Comprehensive molecular pathology analysis of small bowel adenocarcinoma reveals novel targets with clinical utility. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4792. doi:10.1158/1538-7445.AM2015-4792

Juxtapapillary capillary hemangiomas. Clinical features and visual acuity outcomes

OBJECTIVE

To describe the clinical features, association with von Hippel-Lindau (VHL) disease and visual acuity outcomes of patients with a juxtapapillary capillary hemangioma.

DESIGN

Retrospective observational case series.

PARTICIPANTS

Seventy-two eyes of 68 patients identified with a juxtapapillary capillary hemangioma. Follow-up data of at least 6 months duration were available for 60 eyes.

METHODS

A retrospective chart review of patients diagnosed with a juxtapapillary capillary hemangioma examined at four medical centers.

MAIN OUTCOME MEASURES

Age at diagnosis, visual acuity (VA) at first examination and at last follow-up, tumor growth pattern and location, associated clinical features, type of treatment, association with VHL, and presence of peripheral hemangiomas were recorded for each patient.

RESULTS

On initial examination, VA was >/=20/40 in 43 of 70 eyes (61%) and was >/=20/200 in 60 eyes (86%). At an average follow-up of 5.4 years (range, 0.5-19 years), VA of >/=20/40 was achieved in 21 eyes (35%) and >/=20/200 in 33 eyes (55%). Patients with VHL had poorer initial VA (48% vs. 70% with VA >/=20/40, and 74% vs. 93% with VA >/=20/200) and final VA (26% vs. 41% with VA >/=20/40, and 39% vs. 65% with VA >/=20/200) compared with patients without VHL. Patients with VHL more commonly were seen at an earlier age (average, 20 vs. 44 years, P: < 0.001), with bilateral (17% vs. 0%), and/or peripheral (39% vs. 0%) (P: < 0.001) tumors that more often had an endophytic growth pattern (63% vs. 22%, P: = 0.001) compared with patients without VHL. Patients selected for laser treatment generally had poorer initial (52% vs. 74% with VA >/=20/40, 79% vs. 96% with VA >/=20/200) and final VAs (18% vs. 56% with VA >/=20/40, 45% vs. 67% with VA >/=20/200) compared with patients not treated with laser.

CONCLUSIONS

On long-term follow-up of patients with a juxtapapillary capillary hemangioma, the VA generally worsens. Patients with VHL and a juxtapapillary hemangioma more often present at a younger age, have tumors with an endophytic growth pattern, and have bilateral, multiple tumors. Treatment with laser photocoagulation results in variable VA outcomes.

Nonsurgical management of macular hemorrhage secondary to retinal artery macroaneurysms

OBJECTIVE

To report visual acuity outcomes of nonsurgical management of macular hemorrhage secondary to retinal artery macroaneurysms.

METHODS

Forty-one patients at multiple centers with macular hemorrhage secondary to retinal artery macroaneurysms managed with observation alone were reviewed. Time to clearance of macular hemorrhage, visual acuity at final follow-up, and presence or absence of macular pigmentary changes after absorption of the hemorrhage were recorded for each patient.

RESULTS

On initial examination, visual acuity was 20/200 or worse in all except 4 patients (3 with 20/70, 1 with 20/80). At an average follow-up of 15. 7 months, a final visual acuity of 20/40 or better was achieved in 15 eyes (37%), between 20/50 and 20/100 in 12 (29%), and 20/200 or worse in 14 (34%). Macular pigmentary abnormalities were noted after clearance of the hemorrhage in 23 (56%) of 41 cases, and these eyes generally had worse visual acuity outcomes.

CONCLUSIONS

In eyes with macular hemorrhage secondary to retinal artery macroaneurysms managed with observation alone, good visual acuity outcomes can often be achieved. Poorer visual acuity outcomes are associated with macular pigmentary changes after resorption of blood. Arch Ophthalmol. 2000;118:780-785

In vitro efficacy of carboplatin and hyperthermia in a murine retinoblastoma cell line

PURPOSE

To determine the cell-killing activity of varying doses of carboplatin, graded hyperthermia, and the combination of carboplatin and hyperthermia in the treatment of a transgenic murine retinoblastoma cell line.

METHODS

Replicate cell wells (more than six wells per dose point) from an established transgenic murine retinoblastoma cell line (Rb-6) were exposed to a single application of hyperthermia for 15, 30, 60, and 120 minutes at temperatures of 37 degrees C (control), 40 degrees C, and 43 degrees C. Carboplatin dose response treatment was studied at doses of 2000, 1000, 500, 400, 300, 200, 100, and 50 ng per well. Combined treatment studies used these carboplatin dosages with each of the graded hyperthermia exposure temperatures at each exposure time. At 24 hours, all wells were pulsed with 3H-thymidine for 24 hours, washed three times, harvested, and counted. Raw counts (3H-thymidine) were fitted to a linear regression model to calculate the lethal dose for 50% (LD50) of cells.

RESULTS

The LD50 for carboplatin exposure at 37 degrees C occurred at 542 ng. The LD50 for hyperthermia at 40 degrees C occurred at 90 minutes and at 43 degrees C it occurred at 62 minutes. Combined hyperthermia and carboplatin exposure yielded a synergistic interaction with an LD50 of 327 ng at 43 degrees C for 30 minutes. Determination of a thermal enhancement ratio yielded an enhancement range of 1.1 to 25.8.

CONCLUSIONS

The synergistic cytocidal interaction of heat and carboplatin in a transgenic murine retinoblastoma cell line has been established in this study. The increased thermal enhancement ratio documents the potential utility of combined treatment applications in reducing treatment levels of single-modality therapy, potentially allowing for a decrease in treatment-related morbidity.