We successfully established and characterized novel ultra-low passage patient-derived CRC models as useful instruments for analyzing biological characteristics associated with the CIN(+) phenotype.

Malignant melanoma of the uvea is the most common primary malignant tumor in the eye. We aimed to analyze GNAQ and GNA11 mutations in uveal melanomas using formalin-fixed, paraffin-embedded material and correlate the results with clinicopathological parameters. Tumor tissue was microdissected followed by amplification of GNAQ exon 4 and 5, GNA11 exon 4 and 5, and finally analyzed by Sanger sequencing. A total of 64.4 GNA11/GNAQ mutations, including ten yet unreported, were found. Two cases showed multiple mutations. Overall survival was significantly shorter in the uveal melanoma cohort with GNAQ exon 5 mutation. In concordance with previous studies, high frequencies of mutations in GNAQ or GNA11 were detected. Interestingly, in about 20% of UM, not yet reported mutations in GNAQ or GNA11 were seen. Rarely, uveal melanoma may harbor double mutations in GNAQ and/or GNA11. Recent data imply, that implementation of GNAQ/GNA11 mutation analysis in routine diagnostic procedures might be helpful for future therapeutic decisions.

Mismatch-repair deficient (MMR-D) malignancies include Lynch Syndrome (LS), which is secondary to germline mutations in one of the MMR genes, and the rare childhood-form of constitutional mismatch repair-deficiency (CMMR-D); caused by bi-allelic MMR gene mutations. A hallmark of LS-associated cancers is microsatellite instability (MSI), characterized by coding frameshift mutations (cFSM) in target genes. By contrast, tumors arising in CMMR-D patients are thought to display a somatic mutation pattern differing from LS. This study has the main goal to identify cFSM in MSI target genes relevant in CMMR-D and to compare the spectrum of common somatic mutations, including alterations in DNA polymerases POLE and D1 between LS and CMMR-D. CMMR-D-associated tumors harbored more somatic mutations compared to LS cases, especially in the TP53 gene and in POLE and POLD1, where novel mutations were additionally identified. Strikingly, MSI in classical mononucleotide markers BAT40 and CAT25 was frequent in CMMR-D cases. MSI-target gene analysis revealed mutations in CMMR-D-associated tumors, some of them known to be frequently hit in LS, such as RNaseT2, HT001, and TGFβR2. Our results imply a general role for these cFSM as potential new drivers of MMR-D tumorigenesis.

Patient-individual tumor models constitute a powerful platform for basic and translational analyses both in vitro and in vivo. However, due to the labor-intensive and highly time-consuming process, only few well-characterized patient-derived cell lines and/or corresponding xenografts exist. In this study, we describe successful generation and functional analysis of novel tumor models from patients with sporadic primary colorectal carcinomas (CRC) showing CpG island methylator phenotype (CIMP). Initial DNA fingerprint analysis confirmed identity with the patient in all four cases. These freshly established cells showed characteristic features associated with the CIMP-phenotype (HROC40: APCwt, TP53mut, KRASmut; 3/8 marker methylated; HROC43: APCmut, TP53mut, KRASmut; 4/8 marker methylated; HROC60: APCwt, TP53mut, KRASwt; 4/8 marker methylated; HROC183: APCmut, TP53mut, KRASmut; 6/8 marker methylated). Cell lines were of epithelial origin (EpCAM+) with distinct morphology and growth kinetics. Response to chemotherapeutics was quite individual between cells, with stage I-derived cell line HROC60 being most susceptible towards standard clinically approved chemotherapeutics (e.g. 5-FU, Irinotecan). Of note, most cell lines were sensitive towards “non-classical” CRC standard drugs (sensitivity: Gemcitabin > Rapamycin > Nilotinib). This comprehensive analysis of tumor biology, genetic alterations and assessment of chemosensitivity towards a broad range of (chemo-) therapeutics helps bringing forward the concept of personalized tumor therapy.

Colitis-associated colorectal cancer (CAC) seems to be a rather unique entity and differs in its genetic alterations, tumour formation capacities, and clinical features from sporadic colorectal carcinoma. Most descriptions about tumour biology of CAC refer to ulcerative colitis; data about Crohn´s colitis related carcinomas are scarce. The majority of patients with Crohn´s disease are under immunosuppression which generates a different environment for tumour growth. We first describe the clinical case of a fast growing CAC in a long-term immunosuppressed patient with Crohn´s disease and successful establishment and characterization of carcinoma cell lines along with their corresponding patient-derived xenograft. Subsequently, these tumor models were molecularly and functionally analysed. Beside numerous chromosomal alterations, mutations in TP53, APC, PTEN and SMAD3 were identified. The cell lines express numerous cancer testis antigens, surface molecules involved in immune evasion but low levels of HLA class I molecules. They show strong invasive but in comparison weak migratory activity. The present work is the first description of patient-derived in vitro and in vivo models for CAC from a Crohn´s disease patient. They might be valuable tools for analysis of genetic and epigenetic alterations, biomarker identification, functional testing, including response prediction, and the development of specific therapeutical strategies.