Probes for INS

Pan-fibroblast growth-factor receptor (FGFR) inhibitors hold promise in FGFR-altered patients, but such alterations are rare in advanced urothelial carcinoma. In order to assess whether we may increase the number of eligible patients by using different molecular techniques for detecting alterations, we pooled the results of the centralised FGFR mutation/translocation assays that were performed in Clinical Laboratory Improvement Amendments-certified laboratories within multiple phase 2 trials. At our centre, the same tissue blocks were used to analyse FGFR1-3 messenger RNA expression through messenger RNA in situ hybridisation (ISH; RNAscope 2.5 assay). From October 2016 to March 2017, 52 cases were analysed. Seventeen patients (32.7%) had an upper tract primary tumour. Ten patients (19.2%) had FGFR DNA alterations. Twenty-nine (55.8%) had positive ISH analysis: N=17 score 3, N=12 score 4. Of note, concordance between the two tests was obtained in seven out of 10 patients. Sixty percent of mutated patients had an upper tract primary tumour versus 31% of ISH-positive patients.

PATIENT SUMMARY:

We found three-fold higher frequency of fibroblast growth-factor receptor alterations at the RNA versus DNA level in advanced urothelial carcinoma, with a different distribution according to the method used and the site of the primary tumour. The evaluation of the therapeutic response to pan-fibroblast growth-factor receptor inhibitors according to the method of assessment is warranted.

Background: FGFR1 copy number gain (CNG) occurs in head and neck squamous cell cancers (HNSCC) and is used for patient selection in FGFR-specific inhibitor clinical trials. This study explores FGFR1 mRNA and protein levels in HNSCC cell lines, primary tumors and patient-derived xenografts (PDXs) as predictors of sensitivity to the FGFR inhibitor, NVP-BGJ398. Methods: FGFR1 status, expression levels and BGJ398 sensitive growth were measured in 12 HNSCC cell lines. Primary HNSCCs (n=353) were assessed for FGFR1 CNG and mRNA levels and HNSCC TCGA data were interrogated as an independent sample set. HNSCC PDXs (n=39) were submitted to FGFR1 copy number detection and mRNA assays to identify putative FGFR1-dependent tumors. Results: Cell line sensitivity to BGJ398 is associated with FGFR1 mRNA and protein levels, not FGFR1 CNG. 31% of primary HNSCC tumors expressed FGFR1 mRNA, 18% exhibited FGFR1 CNG, 35% of amplified tumors were also positive for FGFR1 mRNA. This relationship was confirmed with the TCGA dataset. Using high FGFR1 mRNA for selection, 2 HNSCC PDXs were identified, one of which also exhibited FGFR1 CNG. The non-amplified tumor with high mRNA levels exhibited in vivo sensitivity to BGJ398. Conclusion: FGFR1 expression associates with BGJ398 sensitivity in HNSCC cell lines and predicts TKI sensitivity in PDXs. Our results support FGFR1 mRNA or protein expression, rather than FGFR1 CNG as a predictive biomarker for the response to FGFR inhibitors in a subset of patients suffering from HNSCC.

Abstract

OBJECTIVES:

Metastatic colorectal cancer (CRC) remains a leading cause of cancer related deaths. Patients with oligometastatic liver disease represent a clinical subgroup with heterogeneous course. Until now, biomarkers to characterize outcome and therapeutic options have not been fully established.

METHODS:

We investigated the prevalence of FGFR alterations in a total of 140 primary colorectal tumors and 63 liver metastases of 55 oligometastatic CRC patients. FGF receptors (FGFR1-4) and their ligands (FGF3, 4 and 19) were analyzed for gene amplifications and rearrangements as well as for RNA overexpression in situ. Results were correlated with clinico-pathologic data and molecular subtypes.

RESULTS:

Primary tumors showed FGFR1 (6.3%) and FGF3,4,19 (2.2%) amplifications as well as FGFR1 (10.1%), FGFR2 (5.5%) and FGFR3 (16.2%) overexpression. In metastases, we observed FGFR1 amplifications (4.8%) as well as FGFR1 (8.5%) and FGFR3 (14.9%) overexpression. Neither FGFR2-4 amplifications nor gene rearrangements were observed. FGFR3 overexpression was significantly associated with shorter overall survival in metastases (mOS 19.9 vs. 47.4 months, HR=3.14, p=0.0152), but not in primary CRC (HR=1.01, p=0.985). Although rare, also FGFR1 amplification was indicative of worse outcome (mOS 12.6 vs. 47.4 months, HR=8.83, p=0.00111).

CONCLUSIONS:

We provide the so far most comprehensive analysis of FGFR alterations in primary and metastatic CRC. We describe FGFR3 overexpression in 15% of CRC patients with oligometastatic liver disease as a prognosticator for poor outcome. Recently FGFR3 overexpression has been shown to be a potential therapeutic target. Therefore, we suggest focusing on this subgroup in upcoming clinical trials with FGFR-targeted therapies.

Abstract

Intratumoral heterogeneity is a major obstacle to cancer treatment and a significant confounding factor in bulk-tumor profiling. We performed an unbiased analysis of transcriptional heterogeneity in colorectal tumors and their microenvironments using single-cell RNA-seq from 11 primary colorectal tumors and matched normal mucosa. To robustly cluster single-cell transcriptomes, we developed reference component analysis (RCA), an algorithm that substantially improves clustering accuracy. Using RCA, we identified two distinct subtypes of cancer-associated fibroblasts (CAFs). Additionally, epithelial-mesenchymal transition (EMT)-related genes were found to be upregulated only in the CAF subpopulation of tumor samples. Notably, colorectal tumors previously assigned to a single subtype on the basis of bulk transcriptomics could be divided into subgroups with divergent survival probability by using single-cell signatures, thus underscoring the prognostic value of our approach. Overall, our results demonstrate that unbiased single-cell RNA-seq profiling of tumor and matched normal samples provides a unique opportunity to characterize aberrant cell states within a tumor.