Alburquerque-González, B.

Conesa Zamora, Pablo

García Solano, José

Gutiérrez García, Irene

Herruzo Priego, Irene

Torres Moreno, Daniel

Turpín Sevilla, María del Carmen

English

DDFV

Study of IDO1 gene expression in histological variants of colorectal carcinomaMaría del Carmen Turpín Sevilla 1,2, José García Solano1 , Irene Gutiérrez García1, Irene Herruzo Priego2, Daniel Torres Moreno1, Begoña Alburquerque González1, Pablo Conesa Zamora11- GI/IMIB/E111/2011- Patología Molecular y Farmacogenética. Departamento de Anatomía Patológica. Hospital General Universitario Santa Lucía (Cartagena)2- Universidad Francisco de Vitoria. Ctra. Pozuelo-Majadahonda KM 1.800. 28223 Pozuelo de Alarcón (Madrid, España)Background: Conventional carcinomas (CCs) which represent most colorectalcarcinomas (CRCs) have no alteration in microsatellite instability (MSI) and areclassified as microsatellite stable tumors (MSS) while tumors with high-grade ofmicrosatellite instability (MSI-H) has been associated with proximal-located sporadicCRC showing MLH1 promoter methylation and BRAF mutation. MSI-H tumorspresent more lymphocytic infiltrate than CCs. MSI-H tumors are considered as oneend-point of the so-called serrated polyp pathway. In contrast, another CRC from thispathway, the serrated adenocarcinoma (SAC), which is more frequently KRASmutated, usually microsatellite stable (MSS) and has no lymphocytic infiltrate, isassociated with a bad prognosis. Patients with MSI-H tumors have been reported toget some benefits from immunotherapy treatments while CC and SACs patients donot obtain any benefits. These differences are believed to be due to the differencesin the microsatellite instability (MSS or MSI tumors). The aim of this study is todetermine the IDO gene expression in the different subtypes of colorectalcarcinomasMaterials and methods: Colorectal carcinoma samples from HospitalGeneral Universitario Santa Lucia (Cartagena) have been classified for cancertype, age, MSS status, T;N;M. RNAs from CCs, SACs and hmMSI-H tumors wereextracted with the miRNeasy kit (ref:217004, Qiagen) and used for validation byqPCR. The retrotranscriptase reaction was performed from a total of 1 µg ofDNAseI-treated RNA using the DyNAmo cDNA synthesis Kit (ref:F470L) providedby Thermo Scientific (Rockford, IL). Five μl of 1:5 diluted cDNA was added tothe qPCR reaction containing 12.5μl 2X QuantiTect SYBR Green PCR Kit(ref:204145, Qiagen) and 300nM of each primer in a total volume of 25μl. qPCRwas performed on a 7500F real time PCR system by Applied Biosystems (FosterCity, CA, USA) according to the instruction manual and following the standardprotocol. Primers used were IDO1, PDL-1, CTLA4 and GAPDH as housekeepinggene.Results: As it is showed in Fig 1, IDO1 expression is higher in MSI-H tumors than in MSS tumors (n=11, p=0,126) but it does not reach statistically significant and do notcorrelationate with PD-L1 (n=11; p=0,662) and CTLA-4 (n=11; p=0,755) expression.In Fig 2, it is analyzed PD-L1 and CTLA4 expression in CC, SAC and MSI-H tumors in the same samples as IDO1, there is a small coincidence between the patterns ofIDO1(n=11; p=0,208) and PD-L1 (n=11; p=0,166) expression and no correlation with CTLA4 (n=11; p=0316) expression.Preliminary results of more samples of CTLA4 and PD-L1 expression (n=39) show CTLA4 expression is higher in SAC than in CC or MSI-H tumors (p=0,44) while thedifference in PD-L1 expression is not statistically significant among the tumors (p=0,906). The difference between MSS and MSI-H tumors was also analyzed but nostatistically differences were found (CTLA4 p=0,317; PD-L1 p=0,460).Conclusions: After this preliminary result, it could be interesting to analyze IDO1 expression in order to decide the best strategy in each tumor. We are working toincrease the number of analyzed samples to confirm this preliminary result.Bibliography1- Clinicopathologic study of 85 colorectal serrated adenocarcinomas: further insights into the full recognition of a new subset of colorectal carcinoma García-Solano, José et al. HumanPathology , Volume 41 , Issue 10 , 1359 – 1368 (2010)2- Colorectal serrated adenocarcinoma shows a different profile of oncogene mutations, MSI status and DNA repair protein expression compared to conventional and sporadic MSI-Hcarcinomas. García-Solano, José et al Int. J. Cancer, 131: 1790–1799. (2012)3- Microsatellite pathologic score does not efficiently identify high microsatellite instability in colorectal serrated adenocarcinoma. García-Solano, José et al. Human Pathology , Volume 44 ,Issue 5 , 759 – 765 (2013)4- Methylome profiling reveals functions and genes which are differentially methylated in serrated compared to conventional colorectal carcinoma. Conesa-Zamora, Pablo et al. ClinicalEpigenetics 7:101 (2015)5-Biomarkers for immune therapy in colorectal cancer: mismatch-repair deficiency and others. Bupathy, Manojkumar and Wu, Christina. J Gastrointest Oncol 7(5):713-720 (2016).6-Inmunotherapy in human colorectal cancer: Challenges and prospective. Sun, Xuan et al. World J Gastroenterol 22(28) 6362-6372 (2016)Fig1 : Comparison of IDO1, CTLA4 and PD-L1 expression between MSS and MSI colon tumorsFig2 : Comparison of IDO1, CTLA4 and PD-L1 expression in the different subtypes of colon tumors

Study of IDO1 gene expression in histological variants of colorectal carcinoma.

http://ddfv.ufv.es/bitstream/10641/3705/1/IDO%201%20poster.pdf

Study of IDO1 gene expression in histological variants of colorectal carcinoma.

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