KRAS and TP53 co-mutation predicts benefit of immune checkpoint blockade in lung adenocarcinoma.

BACKGROUND: Predictive biomarkers in use for immunotherapy in advanced non-small cell lung cancer are of limited sensitivity and specificity. We analysed the potential of activating KRAS and pathogenic TP53 mutations to provide additional predictive information. METHODS: The study cohort included 713 consecutive immunotherapy patients with advanced lung adenocarcinomas, negative for actionable genetic alterations. Additionally, two previously published immunotherapy and two surgical patient cohorts were analyzed. Therapy benefit was stratified by KRAS and TP53 mutations. Molecular characteristics underlying KRASmut/TP53mut tumours were revealed by the analysis of TCGA data. RESULTS: An interaction between KRAS and TP53 mutations was observed in univariate and multivariate analyses of overall survival (Hazard ratio [HR] = 0.56, p = 0.0044 and HR = 0.53, p = 0.0021) resulting in a stronger benefit for KRASmut/TP53mut tumours (HR = 0.71, CI 0.55-0.92). This observation was confirmed in immunotherapy cohorts but not observed in surgical cohorts. Tumour mutational burden, proliferation, and PD-L1 mRNA were significantly higher in TP53-mutated tumours, regardless of KRAS status. Genome-wide expression analysis revealed 64 genes, including CX3CL1 (fractalkine), as specific transcriptomic characteristic of KRASmut/TP53mut tumours. CONCLUSIONS: KRAS/TP53 co-mutation predicts ICI benefit in univariate and multivariate survival analyses and is associated with unique molecular tumour features. Mutation testing of the two genes can be easily implemented using small NGS panels.

Leveraging Off-Target Reads in Panel Sequencing for Homologous Recombination Repair Deficiency Screening in Tumor.

Targeted tumor only sequencing has become a standard practice in cancer diagnostics. This study aims to develop an approach for robust copy number variant calling in tumor samples using only off-target region (OTR) reads. We also established a clinical use case for homologous recombination deficiency (HRD) score estimation (HRDest) using the sum of telomeric-allelic imbalance and large-scale state transition scores without the need for loss of heterozygosity information. A strong correlation was found between HRD score and the sum of telomeric-allelic imbalance + large-scale state transition in The Cancer Genome Atlas cohort (ρ = 0.99, P < 2.2 × 10-16) and in a clinical in-house cohort of 34 tumors (ρ = 0.9, P = 5.1 × 10-13) comparing whole-exome sequencing and targeted sequencing data. HRDest scores from 1086 clinical cases were compared with The Cancer Genome Atlas data set. There were no significant differences in HRD score distribution within the analyzed tumor types. As a control, commercially available HRD standards were also sequenced, and the HRDest scores obtained from the OTR reads were well within the HRD reference range provided by the manufacturer. In conclusion, OTR reads of tumor-only panel sequencing can be used to determine genome-wide copy number variant profiles and to approximate HRD scores.

First-line immunotherapy for lung cancer with MET exon 14 skipping and the relevance of TP53 mutations.

BACKGROUND: The efficacy of checkpoint inhibitors for non-small cell lung cancer (NSCLC) with MET exon 14 skipping (METΔ14ex) remains controversial. MATERIALS AND METHODS: 110 consecutive METΔ14ex NSCLC patients receiving first-line chemotherapy (CHT) and/or immunotherapy (IO) in 10 German centers between 2016-2022 were analyzed. RESULTS: Combined CHT-IO was given to 35/110 (32%) patients, IO alone to 43/110 (39%), and CHT to 32/110 (29%) upfront. Compared to CHT, CHT-IO showed longer progression-free survival (median PFS 6 vs. 2.5 months, p = 0.004), more objective responses (ORR 49% vs. 28%, p = 0.086) and numerically longer overall survival (OS 16 vs. 10 months, p = 0.240). For IO monotherapy, OS (14 vs. 16 months) and duration of response (26 vs. 22 months) were comparable to those of CHT-IO. Primary progressive disease (PD) was more frequent with IO compared to CHT-IO (13/43 vs. 3/35, p = 0.018), particularly for never-smokers (p = 0.041). Higher PD-L1 TPS were not associated with better IO outcomes, but TP53 mutated tumors showed numerically improved ORR (56% vs. 32%, p = 0.088) and PFS (6 vs. 3 months, p = 0.160), as well as longer OS in multivariable analysis (HR=0.54, p = 0.034) compared to their wild-type counterparts. Any second-line treatment was administered to 35/75 (47%) patients, with longer survival for capmatinib or tepotinib compared to crizotinib (PFS 10 vs. 3 months, p = 0.013; OS 16 vs. 13 months, p = 0.270). CONCLUSION: CHT-IO is superior to CHT, and IO alone also effective for METΔ14ex NSCLC, especially in the presence of TP53 mutations and independent of PD-L1 expression, but never-smokers are at higher risk of primary PD.

Genomic heterogeneity at baseline is associated with T790M resistance mutations in EGFR-mutated lung cancer treated with the first-/second-generation tyrosine kinase inhibitors.

This study analyzed whether extended molecular profiling can predict the development of epidermal growth factor receptor (EGFR) gene T790M mutation, which is the most frequent resistance alteration in non-small cell lung cancer (NSCLC) after treatment with the first-/second-generation (1G/2G) EGFR inhibitors (tyrosine kinase inhibitors [TKIs]), but only weakly associated with clinical characteristics. Whole exome sequencing (WES) was performed on pretreatment tumor tissue with matched normal samples from NSCLC patients with (n = 25, detected in tissue or blood rebiopsies) or without (n = 14, negative tissue rebiopsies only) subsequent EGFR p.T790M mutation after treatment with 1G/2G EGFR TKI. Several complex genetic biomarkers were assessed using bioinformatic methods. After treatment with first-line afatinib (44%) or erlotinib/gefitinib (56%), median progression-free survival and overall survival were 12.1 and 33.7 months, respectively. Clinical and tumor genetic characteristics, including age (median, 66 years), sex (74% female), smoking (69% never/light smokers), EGFR mutation type (72% exon 19 deletions), and TP53 mutations (41%) were not significantly associated with T790M mutation (p > 0.05). By contrast, complex biomarkers including tumor mutational burden, the clock-like mutation signature SBS1 + 5, tumor ploidy, and markers of subclonality including mutant-allele tumor heterogeneity, subclonal copy number changes, and median tumor-adjusted variant allele frequency were significantly higher at baseline in tumors with subsequent T790M mutation (all p < 0.05). Each marker alone could predict subsequent development of T790M with an area under the curve (AUC) of 0.72-0.77, but the small number of cases did not allow confirmation of better performance for biomarker combinations in leave-one-out cross-validated logistic regression (AUC 0.69, 95% confidence interval: 0.50-0.87). Extended molecular profiling with WES at initial diagnosis reveals several complex biomarkers associated with subsequent development of T790M resistance mutation in NSCLC patients receiving first-/second-generation TKIs as the first-line therapy. Larger prospective studies will be necessary to define a forecasting model.

Sarcomas With RAD51B Fusions Are Associated With a Heterogeneous Phenotype.

RAD51B-rearranged sarcomas are rare neoplasms that exhibit a heterogeneous morphology. To date, 6 cases have been reported, all involving the uterus, including 4 perivascular epithelioid cell tumors (PEComas) and 2 leiomyosarcomas (LMS). In this study, we describe the morphologic, immunohistochemical, and molecular features of 8 additional sarcomas with RAD51B rearrangement, including the first extrauterine example. All patients were women with a median age of 57 years at presentation. Seven tumors originated in the uterus, and one in the lower extremity soft tissue, with a median tumor size of 12 cm. Histologically, 4 tumors showed predominantly spindle cell morphology with eosinophilic fibrillary cytoplasm, with or without nuclear pleomorphism, whereas 2 tumors exhibited pleomorphic epithelioid cells, featuring clear to eosinophilic, granular cytoplasm. Two neoplasms exhibited undifferentiated cytomorphology, including one with uniform small blue round cells. All tumors showed high-grade cytologic atypia and high mitotic activity (median: 30/10 high-power fields), whereas coagulative necrosis was noted in 6 cases and lymphovascular invasion in 2. By immunohistochemistry, 2 showed myoid and melanocytic markers in keeping with PEComa, whereas 4 cases were only positive for smooth muscle markers consistent with LMS (including 3 myxoid). The remaining 2 cases had a nonspecific immunoprofile. Five cases tested by targeted RNA sequencing (Archer FusionPlex, Illumina TruSight) showed different fusion partners (HMGA2, PDDC1, and CEP170). RAD51B rearrangements were identified by FISH in the remaining 3 cases. Targeted DNA sequencing in 2 cases was negative for TSC gene alterations. Clinical outcome, available in 5 patients (median follow-up, 19 months), revealed 3 local recurrences, 2 lung metastases, and 4 deaths due to disease. Our results expand the spectrum of sarcomas with RAD51B fusions, demonstrating variable clinical presentations, morphologic spectrum, and fusion partners. These tumors have a predilection for a uterine location, with either LMS, PEComa, or undifferentiated phenotypes, and are associated with an aggressive clinical course.

Nivolumab and ipilimumab in recurrent or refractory cancer of unknown primary: a phase II trial.

Cancer of unknown primary has a dismal prognosis, especially following failure of platinum-based chemotherapy. 10-20% of patients have a high tumor mutational burden (TMB), which predicts response to immunotherapy in many cancer types. In this prospective, non-randomized, open-label, multicenter Phase II trial (EudraCT 2018-004562-33; NCT04131621), patients relapsed or refractory after platinum-based chemotherapy received nivolumab and ipilimumab following TMBhigh vs. TMBlow stratification. Progression-free survival (PFS) represented the primary endpoint; overall survival (OS), response rates, duration of clinical benefit and safety were the secondary endpoints. The trial was prematurely terminated in March 2021 before reaching the preplanned sample size (n = 194). Among 31 evaluable patients, 16% had a high TMB ( > 12 mutations/Mb). Overall response rate was 16% (95% CI 6-34%), with 7.7% (95% CI 1-25%) vs. 60% (95% CI 15-95%) in TMBlow and TMBhigh, respectively. Although the primary endpoint was not met, high TMB was associated with better median PFS (18.3 vs. 2.4 months) and OS (18.3 vs. 3.6 months). Severe immune-related adverse events were reported in 29% of cases. Assessing on-treatment dynamics of circulating tumor DNA using combined targeted hotspot mutation and shallow whole genome sequencing as part of a predefined exploratory analysis identified patients benefiting from immunotherapy irrespective of initial radiologic response.

Multicentric pilot study to standardize clinical whole exome sequencing (WES) for cancer patients.

A growing number of druggable targets and national initiatives for precision oncology necessitate broad genomic profiling for many cancer patients. Whole exome sequencing (WES) offers unbiased analysis of the entire coding sequence, segmentation-based detection of copy number alterations (CNAs), and accurate determination of complex biomarkers including tumor mutational burden (TMB), homologous recombination repair deficiency (HRD), and microsatellite instability (MSI). To assess the inter-institution variability of clinical WES, we performed a comparative pilot study between German Centers of Personalized Medicine (ZPMs) from five participating institutions. Tumor and matched normal DNA from 30 patients were analyzed using custom sequencing protocols and bioinformatic pipelines. Calling of somatic variants was highly concordant with a positive percentage agreement (PPA) between 91 and 95% and a positive predictive value (PPV) between 82 and 95% compared with a three-institution consensus and full agreement for 16 of 17 druggable targets. Explanations for deviations included low VAF or coverage, differing annotations, and different filter protocols. CNAs showed overall agreement in 76% for the genomic sequence with high wet-lab variability. Complex biomarkers correlated strongly between institutions (HRD: 0.79-1, TMB: 0.97-0.99) and all institutions agreed on microsatellite instability. This study will contribute to the development of quality control frameworks for comprehensive genomic profiling and sheds light onto parameters that require stringent standardization.

Integrated genotype-phenotype analysis of familial adenomatous polyposis-associated hepatocellular adenomas.

Familial adenomatous polyposis (FAP) is an autosomal dominant syndrome caused by a germline mutation in the adenomatous polyposis coli (APC) gene, characterized by numerous colorectal adenomas. In addition, FAP patients may develop extraintestinal manifestations. Several cases of hepatocellular adenomas (HCA) detected accidentally in FAP patients have raised the so-far unsolved question of whether they represent a specific manifestation of FAP or a mere coincidence. To investigate the incidence of liver tumors in FAP patients, we analyzed our diagnostic database from 1991 to 2021. Among the 58 hepatic mass lesions identified, five HCAs occurring in three patients with FAP were identified, and comprehensive morphological, immunohistological, and molecular analysis employing targeted next-generation sequencing was conducted for characterization. The HCAs in this study showed no cytological or histological atypia. They displayed a diffuse, strong positivity for glutamine synthetase but no nuclear beta-catenin immunostaining. In two patients, the adenomas showed moderate immunoreactivity against serum amyloid A. Consistent with the diagnosis of FAP, molecular profiling revealed a pathogenic germline mutation of the APC gene in all analyzed adenomas as well as deleterious somatic second hits. All somatic mutations were localized between codons 1345 and 1577. No mutations were found in the catenin beta 1 gene. HCA in FAP patients can be a specific, although rare, neoplastic manifestation of this inborn disease and represents a distinct subgroup of HCAs. These benign tumors represent an important differential diagnosis for hepatic metastases in FAP patients and require adequate clinical and molecular (diagnostic) assessments for optimal patient guidance.

Digital Spatial Profiling Identifies the Tumor Periphery as a Highly Active Biological Niche in Clear Cell Renal Cell Carcinoma.

Clear cell renal cell carcinoma (ccRCC) is characterized by a high degree of intratumoral heterogeneity (ITH). Besides genomic ITH, there is considerable functional ITH, which encompasses spatial niches with distinct proliferative and signaling activities. The full extent of functional spatial heterogeneity in ccRCC is incompletely understood. In the present study, a total of 17 ccRCC tissue specimens from different sites (primary tumor, n = 11; local recurrence, n = 1; distant metastasis, n = 5) were analyzed using digital spatial profiling (DSP) of protein expression. A total of 128 regions of interest from the tumor periphery and tumor center were analyzed for the expression of 46 proteins, comprising three major signaling pathways as well as immune cell markers. Results were correlated to clinico-pathological variables. The differential expression of granzyme B was validated using conventional immunohistochemistry and was correlated to the cancer-specific patient survival. We found that a total of 37 proteins were differentially expressed between the tumor periphery and tumor center. Thirty-five of the proteins were upregulated in the tumor periphery compared to the center. These included proteins involved in cell proliferation, MAPK and PI3K/AKT signaling, apoptosis regulation, epithelial-to-mesenchymal transition, as well as immune cell markers. Among the most significantly upregulated proteins in the tumor periphery was granzyme B. Granzyme B upregulation in the tumor periphery correlated with a significantly reduced cancer-specific patient survival. In conclusion, this study highlights the unique cellular contexture of the tumor periphery in ccRCC. The correlation between granzyme B upregulation in the tumor periphery and patient survival suggests local selection pressure for aggressive tumor growth and disease progression. Our results underscore the potential of spatial biology for biomarker discovery in ccRCC and cancer in general.

Spatial profiling of the microenvironment reveals low intratumoral heterogeneity and STK11-associated immune evasion in therapy-naïve lung adenocarcinomas.

OBJECTIVE: Intratumoral heterogeneity was found to be a significant factor causing resistance to lung cancer therapies, including immune checkpoint blockade. Lesser is known about spatial heterogeneity of the tumor microenvironment (TME) and its association with genetic properties of the tumor, which is of particular interest in the therapy-naïve setting. MATERIALS AND METHODS: We performed multi-region sampling (2-4 samples per tumor; total of 55 samples) from a cohort of 19 untreated stage IA-IIIB lung adenocarcinomas (n = 11 KRAS mutant, n = 1 ERBB2 mutant, n = 7 KRAS wildtype). For each sample the expression of 770 immunooncology-related genes was analyzed using the nCounter platform, while the mutational status was determined by hybrid capture-based next-generation sequencing (NGS) using a large panel covering more than 500 genes. RESULTS: Global unsupervised analyses revealed clustering of the samples into two groups corresponding to a 'hot' or 'cold' immunologic tumor contexture based on the abundance of immune cell infiltrates. All analyzed specific immune cell signatures (ICsig) showed a significantly higher intertumoral than intratumoral heterogeneity (p < 0.02), as most of the analyzed cases (14/19) showed a very homogenous spatial immune cell profile. PD-L1 exhibited a significantly higher intertumoral than intratumoral heterogeneity (p = 1.03e-13). We found a specific association with 'cold' TME for STK11 (11/14, p < 0.07), but not KRAS, TP53, LRP1B, MTOR, U2AF1 co-mutations, and validated this finding using The Cancer Genome Atlas (TCGA) data. CONCLUSION: Early-stage lung adenocarcinomas show considerable intertumoral, but limited intratumoral heterogeneity, which is clinically highly relevant as assessment before neoadjuvant treatment is based on small biopsies. STK11 mutations are specifically associated with a 'cold' TME, which could affect the efficacy of perioperative immunotherapy.

First proficiency testing for NGS-based and combined NGS- and FISH-based detection of FGFR2 fusions in intrahepatic cholangiocarcinoma.

Intrahepatic cholangiocarcinoma harbours druggable genetic lesions including FGFR2 gene fusions. Reliable and accurate detection of these fusions is becoming a critical component of the molecular work-up, but real-world data on the performance of fluorescence in situ hybridisation (FISH) and targeted RNA-based next-generation sequencing (NGS) are very limited. Bridging this gap, we report results of the first round robin test for FGFR2 fusions in cholangiocarcinoma and contextualise test data with genomic architecture. A cohort of 10 cholangiocarcinoma (4 fusion positive and 6 fusion negative) was tested by the Institute of Pathology, University Hospital Heidelberg, Germany. Data were validated by four academic pathology departments in Germany. Fusion-positive cases comprised FGFR2::BICC1, FGFR2::DBP, FGFR2::TRIM8, and FGFR2::ATE1 fusions. In a second step, a round robin test involving 21 academic and non-academic centres testing with RNA-based NGS approaches was carried out; five participants performed FISH testing in addition. Thirteen of 16 (81%) centres successfully passed the NGS only and 3 of 5 (60%) centres passed the combined NGS + FISH round robin test. Identified obstacles were bioinformatic pipelines not optimised for the detection of FGFR2 fusions and assays not capable of detecting unknown fusion partners. This study shows the benefit of targeted RNA-NGS for the detection of FGFR2 gene fusions. Due to the marked heterogeneity of the genomic architecture of these fusions, fusion partner agnostic (i.e. open) methodological approaches that are capable of identifying yet unknown fusion partners are superior. Furthermore, we highlight pitfalls in subsequent bioinformatic analysis and limitations of FISH-based tests.

Expanding the molecular spectrum of gene fusions in endometrial stromal sarcoma: Novel subunits of the chromatin remodeling complexes PRC2 and NuA4/TIP60 as alternative fusion partners.

Endometrial stromal sarcomas (ESS) are morphologically and molecularly heterogeneous. We report novel gene fusions (EPC1::EED, EPC1::EZH2, ING3::PHF1) identified by targeted RNA sequencing in five cases. The ING3::PHF1-fusion positive ESS presented in a 58-year-old female as extrauterine mesocolonic, ovarian masses, and displayed large, monomorphic ovoid-to-epithelioid cells arranged in solid sheets. The patient remained alive with disease 13 months after surgery. The three ESS with EPC1::EED occurred in the uterine corpus in patients with a median age of 58 years (range 27-62 years). One tumor showed a uniform epithelioid nested morphology, while the other two were composed of monomorphic spindle cells in fascicles with elevated mitotic figures, focal tumor cell necrosis, and lymphovascular invasion. At a median follow-up of 20 months, two patients developed local recurrence, including one with concomitant distant metastasis, while one patient remained free of disease. All three patients were alive at the last follow-up. The EPC1::EZH2-fusion positive ESS presented in a 52-year-old female in the uterus, and displayed uniform spindled cells arranged in short fascicles, with focally elevated mitotic activity but without necrosis. The patient remained free of disease 3 months after surgery. All cases were diffusely positive for CD10; four diffusely express estrogen and progesterone receptors. Our study expands the molecular spectrum of EPC1 and PHF1-related gene fusions in ESS to include additional novel subunits of the PRC2 and/or NuA4/TIP60 complexes. These cases displayed a monomorphic epithelioid or spindled phenotype, spanning low-grade and high-grade cytomorphology, all expressing CD10 and commonly ER and PR, and are prone to local and/or distant spread.

BAP1 and PTEN mutations shape the immunological landscape of clear cell renal cell carcinoma and reveal the intertumoral heterogeneity of T cell suppression: a proof-of-concept study.

Clear cell renal cell carcinoma (ccRCC) is an immunologically vulnerable tumor entity, and immune checkpoint inhibitors are now widely used to treat patients with advanced disease. Whether and to what extent immune responses in ccRCC are shaped by genetic alterations, however, is only beginning to emerge. In this proof-of-concept study, we performed a detailed correlative analysis of the mutational and immunological landscapes in a series of 23 consecutive kidney cancer patients. We discovered that a high infiltration with CD8 + T cells was not dependent on the number of driver mutations but rather on the presence of specific mutational events, namely pathogenic mutations in PTEN or BAP1. This observation encouraged us to compare mechanisms of T cell suppression in the context of four different genetic patterns, i.e., the presence of multiple drivers, a PTEN or BAP1 mutation, or the absence of detectable driver mutations. We found that ccRCCs harboring a PTEN or BAP1 mutation showed the lowest level of Granzyme B positive tumor-infiltrating lymphocytes (TILs). A multiplex immunofluorescence analysis revealed a significant number of CD8 + TILs in the vicinity of CD68 + macrophages/monocytes in the context of a BAP1 mutation but not in the context of a PTEN mutation. In line with this finding, direct interactions between CD8 + TILs and CD163 + M2-polarized macrophages were found in BAP1-mutated ccRCC but not in tumors with other mutational patterns. While an absence of driver mutations was associated with more CD8 + TILs in the vicinity of FOXP3 + Tregs and CD68 + monocytes/macrophages, the presence of multiple driver mutations was, to our surprise, not found to be strongly associated with immunosuppressive mechanisms. Our results highlight the role of genetic alterations in shaping the immunological landscape of ccRCC. We discovered a remarkable heterogeneity of mechanisms that can lead to T cell suppression, which supports the need for personalized immune oncological approaches.

Lorlatinib and compound mutations in ALK+ large-cell neuroendocrine lung carcinoma: a case report.

Large-cell neuroendocrine lung carcinoma (LCNEC) is a high-grade neoplasm with median survival of 1 year and limited therapeutic options. Here, we report the unusual case of a 47-yr-old female smoker with stage IV LCNEC featuring EML4-ALK variant 2 (E20:A20), wild-type TP53/RB1, and low tumor mutational burden of 3.91 mut/Mb. Despite early progression within 3 mo under crizotinib, a durable response was achieved with alectinib. Oligoprogression in the left breast 10 mo later was treated by surgery, followed by a switch to ceritinib upon multifocal progression and detection of ALK:p.V1180L in the mastectomy specimen, but without success. Another rebiopsy revealed ALK:p.L1196M, but the tumor did not respond to brigatinib or carboplatin/pemetrexed, before stabilization under lorlatinib. Diffuse progression 8 mo later with detection of ALK :p.L1196M/p.G1202R and p.L1196M/ p.D1203N evolving from the previous p.L1196M did not respond to chemoimmunotherapy, and the patient succumbed with an overall survival (OS) of 37 mo. This case illustrates the importance of molecular profiling for LCNEC regardless of smoking status, and the superiority of next-generation ALK inhibitors compared to crizotinib for ALK+ cases. Lorlatinib retained efficacy in the heavily pretreated setting, whereas its upfront use could possibly have prevented the stepwise emergence of compound ALK mutations. Furthermore, the disease course was more aggressive and OS shorter compared to the V2/TP53wt ALK+ lung adenocarcinoma, whereas crizotinib, ceritinib, and brigatinib did not confer the benefit expected according to next-generation sequencing results, which also underline the need for more potent drugs against ALK in the high-risk setting of neuroendocrine histology.

Genomic architecture of FGFR2 fusions in cholangiocarcinoma and its implication for molecular testing.

BACKGROUND: Cholangiocarcinoma (CCA) is a primary malignancy of the biliary tract with a dismal prognosis. Recently, several actionable genetic aberrations were identified with significant enrichment in intrahepatic CCA, including FGFR2 gene fusions with a prevalence of 10-15%. Recent clinical data demonstrate that these fusions are druggable in a second-line setting in advanced/metastatic disease and the efficacy in earlier lines of therapy is being evaluated in ongoing clinical trials. This scenario warrants standardised molecular profiling of these tumours. METHODS: A detailed analysis of the original genetic data from the FIGHT-202 trial, on which the approval of Pemigatinib was based, was conducted. RESULTS: Comparing different detection approaches and displaying representative cases, we described the genetic landscape and architecture of FGFR2 fusions in iCCA and show biological and technical aspects to be considered for their detection. We elaborated parameters, including a suggestion for annotation, that should be stated in a molecular diagnostic FGFR2 report to allow a complete understanding of the analysis performed and the information provided. CONCLUSION: This study provides a detailed presentation and dissection of the technical and biological aspects regarding FGFR2 fusion detection, which aims to support molecular pathologists, pathologists and clinicians in diagnostics, reporting of the results and decision-making.

The impact of TP53 co-mutations and immunologic microenvironment on outcome of lung cancer with EGFR exon 20 insertions.

BACKGROUND: EGFR exon20 insertions (ex20ins) are targeted by novel compounds in non-small-cell lung cancer (NSCLC). However, data about outcome under conventional therapies and the influence of molecular features are scarce. PATIENTS AND METHODS: We retrospectively analysed 118 patients with evaluation of radiologic response based on RECIST v1.1. TP53 status was available for 88 cases. RESULTS: Platinum doublets and chemoimmunotherapy showed similar response rates (20-25%), disease control rates (80%) and median progression-free survival (mPFS, ≈7 months), which were longer compared to monochemotherapy (9%, 59%, 4.1 months), EGFR inhibitors (0%, 46%, 3.0) and PD-(L)1 inhibitors (0%, 30%, 2.1; p < 0.05). Overall survival (OS) was not dependent on the choice of first-line treatment, but related to more lines of systemic therapy (p < 0.05). TP53 mutations and brain metastases were associated with shorter PFS under platinum doublets and EGFR inhibitors (HR 3.3-6.1, p < 0.01), and shorter OS for patients receiving both treatments (p < 0.05). More tumour CD8+ and less Th1 cells were associated with longer OS independent of brain and TP53 status (p < 0.01). No difference in outcome was noted according to the ex20ins site and use of pemetrexed (vs. other cytotoxics) or bevacizumab. Long-lasting responses (>1 year) occasionally occurred under EGFR inhibitors for both 'near-' and 'far-loop' variants. CONCLUSIONS: Platinum doublets and chemoimmunotherapy have the highest activity with ORR of 20-25% and mPFS of approximately 7 months, regardless of the cytotoxic partner, while PD-(L)1 inhibitors show limited efficacy. TP53 mutations, brain metastases and a lower tumour CD8/Th1-cell ratio are independently associated with shorter survival.

Histological and molecular plasticity of ALK-positive non-small-cell lung cancer under targeted therapy: a case report.

With medical progress in cancer therapy, tyrosine kinase inhibitors (TKIs) became a standard of care for many cancer types. But the broad range of possible targeted therapies was accompanied by a plethora of potential resistance mechanisms, of which many have still to be identified. Here, we present the case of a patient with an EML4-ALK translocated non-small-cell lung cancer treated with four different TKIs. Her tumor developed not only a well-known ALK-TKI resistance mutation but also underwent a histological transformation from adenocarcinoma to squamous cell carcinoma. To confirm a shared monoclonal origin of the phenotypically different tumors, a phylogenetic reconstruction was conducted: This revealed a cluster of mutations including NFE2L2, KMT2D, and MLH1, which are possible triggering events for the transformation.

Assigning evidence to actionability: An introduction to variant interpretation in precision cancer medicine.

Modern concepts in precision cancer medicine are based on increasingly complex genomic analyses and require standardized criteria for the functional evaluation and reporting of detected genomic alterations in order to assess their clinical relevance. In this article, we propose and address the necessary steps in systematic variant evaluation consisting of bioinformatic analysis, functional annotation and clinical interpretation, focusing on the latter two aspects. We discuss the role and clinical application of current variant classification systems and point out their scope and limitations. Finally, we highlight the significance of the molecular tumor board as a platform for clinical decision-making based on genomic analyses.

The Different Immune Profiles of Normal Colonic Mucosa in Cancer-Free Lynch Syndrome Carriers and Lynch Syndrome Colorectal Cancer Patients.

BACKGROUND & AIMS: Owing to the high load of immunogenic frameshift neoantigens, tumors arising in individuals with Lynch syndrome (LS), the most common inherited colorectal cancer (CRC) syndrome, are characterized by a pronounced immune infiltration. However, the immune status of normal colorectal mucosa in LS is not well characterized. We assessed the immune infiltrate in tumor-distant normal colorectal mucosa from LS CRC patients, sporadic microsatellite-unstable (MSI) and microsatellite-stable (MSS) CRC patients, and cancer-free LS carriers. METHODS: CD3-positive, FOXP3-positive, and CD8-positive T cells were quantified in, respectively, 219, 233, and 201 formalin-fixed paraffin-embedded (FFPE) normal colonic mucosa tissue sections from CRC patients and cancer-free LS carriers and 26, 22, and 19 LS CRCs. CD3-positive T cells were also quantified in an independent cohort of 97 FFPE normal rectal mucosa tissue sections from LS carriers enrolled in the CAPP2 clinical trial. The expression of 770 immune-relevant genes was analyzed in a subset of samples with the use of the NanoString nCounter platform. RESULTS: LS normal mucosa specimens showed significantly elevated CD3-, FOXP3-, and CD8-positive T-cell densities compared with non-LS control specimens. Gene expression profiling and cluster analysis revealed distinct immune profiles in LS carrier mucosa with and without cancer manifestation. Long-term follow-up of LS carriers within the CAPP2 trial found a correlation between mucosal T-cell infiltrate and time to subsequent tumor occurrence. CONCLUSIONS: LS carriers show elevated mucosal T-cell infiltration even in the absence of cancer. The normal mucosa immune profile may be a temporary or permanent tumor risk modifier in LS carriers.