P53 in Penile Squamous Cell Carcinoma: A Pattern-Based Immunohistochemical Framework with Molecular Correlation

p53 immunohistochemistry (IHC) has been proposed as a surrogate for TP53 mutations in penile squamous cell carcinomas (PSCC). We aimed to evaluate the performance of a pattern-based evaluation of p53 IHC in PSCC. Human papilloma virus (HPV) DNA testing, p16 and p53 IHC, and whole exome sequencing were performed in a series of 40 PSCC. p53 IHC was evaluated following a pattern-based framework and conventional p53 IHC evaluation. Out of 40 PSCC, 12 (30.0%) were HPV-associated, and 28 (70.0%) were HPV-independent. The agreement between the p53 IHC pattern-based evaluation and TP53 mutational status was almost perfect (k = 0.85). The sensitivity and accuracy of the pattern-based framework for identifying TP53 mutations were 95.5% and 92.5%, respectively, which were higher than the values of conventional p53 IHC interpretation (54.5% and 70.0%, respectively), whereas the specificity was the same (88.9%). In conclusions, the pattern-based framework improves the accuracy of detecting TP53 mutations in PSCC compared to the classical p53 IHC evaluation.

Development and validation of a gene expression signature based on RB1, PTEN,and TP53 in patients with metastatic hormone-sensitive prostate cancer (mHSPC)

236

Background: Alterations on the tumor suppressor genes (TSG) RB1, PTEN and TP53 are associated with treatment resistance and aggressive clinical evolution of prostate cancer patients (pts). We developed and assessed the role of a TSG gene expression signature in mHSPC pts. Methods: This is a multicenter retrospective biomarker study in mHSPC pts receiving different therapies. RB1, PTEN and TP53 mutations were assessed by targeted sequencing and its gene expression was determined by the nCounter platform in FFPE tumor samples. Normalized and transformed (z-score) expression data of a training cohort was used to establish the cut-off for RB1, PTEN and TP53 expression, those cut-offs were then applied to the other cohorts. TSGlow was considered when ≥2 out of 3 TSG presented low expression, and TSGwt in the remaining cases. TSG signature was correlated with castration resistance-free survival (CRPC-FS) (primary endpoint) and overall survival (OS) by Kaplan Meier and multivariate Cox analysis. Results: Overall, 297 pts (baseline characteristics are shown) were included: 125 treated with ADT+Docetaxel (ADT+D) (54 and 71 in training and validation cohorts, respectively), 93 with ADT, and 79 with ADT+Abiraterone or Enzalutamide (ADT+A/E). Training cohort pts were tested for both, gene expression and targeted sequencing of TSG. Pts with low expression of PTEN showed higher frequency of PTEN mutations (p<0.05). TSGlow (14 (25.9%) out of 54 pts) had a worse CRPC-FS (14.3 vs. 21.7 months (m); HR 2.2 (95% CI, 1.1 - 4.4), p=0.022). In the validation cohort, 7 (9.9%) pts were TSGlow and had a worse CPRC-FS (11.7 vs. 20 m, HR 2.5 (95% CI, 1.1 - 5.5), p=0.027) and OS (27.6 vs 58.1 m, HR 3.5 (95% CI, 1.3 - 9.5) p=0.012). TSGlow signature was independently associated with CPRC-FS (HR 2.66 (95% CI, 1.17 - 6.06), p=0.02) and OS (HR 3.67 (95% CI, 1.33 - 10.10), p=0.012). In the ADT and ADT+A/E cohorts, 20 (21.5%) and 14 (17.7%) pts were TSGlow, respectively. TSGlow was not predictive of either CRPC-FS (p=0.23 and p=0.242, respectively) or OS (p=0.091 and p=0.66, respectively). We analyzed together high-volume pts from both ADT+D and ADT cohorts. TSGlow pts (16, 10.74%) treated with ADT+D had a CRPC-FS (13.6 m) similar to pts treated with ADT (TSGlow = 14.5 m and TSGwt = 12.8 m). Moreover, TSGwt pts treated with ADT+D had a better CRPC-FS (19.3m) (p=0.022) and OS (ADT/TSGlow = 31.7 m, ADT/TSGwt = 38.6 m, ADT+D/TSGlow = 31.5 m, ADT+D/TSGwt = 52.2 m, p=0.07). Conclusions: A TSG gene expression signature is predictive of taxanes benefit in mHSPC pts and may be useful to personalize the treatment in this setting. [Table: see text]

Histone H4 acetylation is dysregulated in active seminiferous tubules adjacent to testicular tumours

STUDY QUESTION

Is histone H4 acetylation (H4ac) altered in the seminiferous tubules of patients affected by testicular tumours?

SUMMARY ANSWER

A considerable dysregulation of H4ac was detected in the cells of the seminiferous tubules adjacent to testicular tumours of different aetiology and prior to any treatment, while no comparable alterations were observed in patients with disrupted spermatogenesis.

WHAT IS KNOWN ALREADY

Altered H4ac levels have been associated with a variety of testicular pathological conditions. However, no information has been available regarding potential alterations in the spermatogenic cells adjacent to the neoplasia in testicular tumour patients.

STUDY DESIGN, SIZE, DURATION

A retrospective analysis using testicular sections from 33 men aged between 21 and 74 years old was performed. Three study groups were defined and subjected to double-blind evaluation: a control group with normal spermatogenesis (n = 6), patients with testicular tumours (n = 18) and patients with spermatogenic impairments (n = 8). One additional sample with normal spermatogenesis was used as a technical internal control in all evaluations.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Immunohistochemistry against H4ac and, when needed, Placental-like alkaline phosphatase and CD117, was performed on testicular sections. The H4ac H-score, based on the percentage of detection and signal intensity, was used as the scoring method for statistical analyses. Protein expression data from the Human Protein Atlas were used to compare the expression levels of predicted secreted proteins from testicular tumours with those present in the normal tissue.

MAIN RESULTS AND THE ROLE OF CHANCE

We revealed, for the first time, a dramatic disruption of the spermatogenic H4ac pattern in unaffected seminiferous tubule cells from different testicular tumour patients prior to any antineoplastic treatment, as compared to controls (P < 0.05). Since no similar alterations were associated with spermatogenic impairments and the in silico analysis revealed proteins potentially secreted by the tumour to the testicular stroma, we propose a potential paracrine effect of the neoplasia as a mechanistic hypothesis for this dysregulation.

LIMITATIONS, REASONS FOR CAUTION

Statistical analyses were not performed on the hypospermatogenesis and Leydig cell tumour groups due to limited availability of samples.

WIDER IMPLICATIONS OF THE FINDINGS

To the best of our knowledge, this is the first report showing an epigenetic alteration in cells from active seminiferous tubules adjacent to tumour cells in testicular tumour patients. Our results suggest that, despite presenting spermatogenic activity, the global epigenetic dysregulation found in the testicular tumour patients could lead to molecular alterations of the male germ cells. Since testicular tumours are normally diagnosed in men at reproductive age, H4ac alterations might have an impact when these testicular tumour patients express a desire for fatherhood.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the European Union Marie Curie European Training Network actions and by grants to R.O. from the 'Ministerio de Economía y Competividad (Spain)' (fondos FEDER 'una manera de hacer Europa', PI13/00699, PI16/00346 and PI20/00936) and from EU-FP7-PEOPLE-2011-ITN289880. J.C. was supported by the Sara Borrell Postdoctoral Fellowship, Acción Estratégica en Salud, CD17/00109. J.C. is a Serra Húnter fellow (Universitat de Barcelona, Generalitat de Catalunya). F.B. has received grants from the Ministerio de Educación, Cultura y Deporte para la Formación de Profesorado Universitario (Spain) (FPU15/02306). A.d.l.I. is supported by a fellowship of the Ministerio de Economía, Industria y Competitividad (Spain) (PFIS, FI17/00224). M.J. is supported by the Government of Catalonia (Generalitat de Catalunya, pla estratègic de recerca i innovació en salut, PERIS 2016-2020, SLT002/16/00337). The authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Estrogen receptor β and TMPRSS2-ERG expression association with clinical outcomes in metastatic hormone-sensitive prostate cancer

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Background: TMPRSS2-ERG fusion has been associated with estrogen receptor (ER) signalling in prostate cancer (PC). The isoform beta of ER (ERβ), encoded by ESR2, is considered anti-proliferative and tumor-suppressive. In preclinical studies, ESR2 has shown an inhibitory role towards TMPRSS2-ERG, resulting in decreased proliferation and tumor regression. In this clinical series, we sought to investigate the correlation between TMPRSS2-ERG and ESR2 expression and its impact on clinical outcomes in a cohort of patients (pts) with metastatic hormone-sensitive PC (mHSPC). Methods: This is a multicenter retrospective biomarker study. TMPRSS2-ERG and ESR2 were tested in total mRNA from FFPE tumor samples by nCounter platform (Nanostring Technologies). TMPRSS2-ERG and ESR2 expression were correlated with castration-resistant PC free survival (CRPC-FS) and overall survival (OS) by Kaplan Meier and multivariate Cox modeling. R (v.3.6.3) software was used for statistical analysis. Results: 218 mHSPC pts were included: 125 received androgen deprivation therapy (ADT) with Docetaxel and 93 ADT alone. Median age was 66.4 years (range 46.3-84.6), 75.7% ( N= 165) presented with de novo mHSPC, 15.1% ( N= 33) had visceral metastasis and 68.3% ( N= 149) had high volume disease. Median follow-up was 38.8 months (m) (range 6.7-223.5) and 189 pts (86.7%) developed CRPC. Five pts were excluded due to lack of follow-up. Median time to CRPC was 18.8 m (95% CI 15.8-20.5) and median OS was 48.8 m (95% CI 43.2-59.1). Pts were grouped according to TMPRSS2-ERG fusion detection in TE positive (TE+) ( N= 108, 49.5%) and TE negative (TE-) ( N= 110, 50.5%) and according to ESR2 expression levels segregated into tertiles in ESR2 high (ESR2+) ( N= 74, 33.9%) or ESR2 low-mid (ESR2-) ( N= 144, 66.1%). TE+ status was associated to higher ESR2 levels ( P= 0.03). The TE+/ESR2+ group showed longer CRPC-FS and OS, compared with the other groups, as shown in the table. TE+/ESR2 expression was independently associated with longer CRPC-FS (HR 0.3, 95% CI 0.2-0.5, P< 0.001) and OS (HR 0.3, 95% CI 0.2-0.5, P< 0.001). Moreover, a significant interaction between treatment (ADT vs ADT+Docetaxel) and TE+/ESR2+ status related to CRPC-FS was found (HR: 0.38, P= 0.014), suggesting that TE+/ESR2+ pts may benefit more from ADT than from the combination of ADT+Docetaxel. Conclusions: Our study suggests a protective role of ESR2 within a subgroup of mHSPC pts characterized by TMPRSS2-ERG fusion, which warrants further investigation of ESR2 as a prognostic factor, for treatment selection and as a potential pathway for targeted treatment in PC. [Table: see text]

Association of androgen receptor signature and RB1, PTEN, TP53 gene expression with clinical outcome in metastatic hormone-sensitive prostate cancer treated with docetaxel and androgen deprivation therapy

5069

Background: Androgen deprivation therapy (ADT) with docetaxel or new antiandrogens has demonstrated a survival benefit in metastatic hormone-sensitive prostate cancer (mHSPC). However, treatment selection for individual patients (pts) remains a challenge. We propose that TMPRSS2-ERG and cell plasticity [neuroendocrine (NE), epithelial to mesenchymal transition (EMT)], immune-related, androgen receptor (AR) and tumor suppressor genes (TSG) ( RB1, PTEN and TP53) expression signatures may predict clinical outcome in mHSPC pts treated with ADT+docetaxel. Methods: This is a multicenter retrospective biomarker study performed in mHSPC pts treated with ADT+docetaxel. A customized panel of 184 genes was designed and tested in total mRNA from FFPE tumor samples by nCounter platform (Nanostring Technologies). Expression levels were correlated with castration resistance-free survival (CRPC-FS) (primary endpoint) and overall survival (OS) by Kaplan Meier and multivariate Cox modeling. A predictive modeling approach was performed with Bujar R package to develop a signature able to predict CRPC-FS. R (v.3.6.3) software was used for statistical analyses. Results: 136 pts were included, and 120 of them were eligible. Median age was 66.9 years (range 46.3-83.6). Gleason score was ≥ 8 in 80.8% of pts; 87.5% and 20.8% of pts had bone and visceral metastases, respectively. Median follow-up was 30.7 months (m) (range 5.5-70.6). 76 pts (63.3%) developed castration-resistant prostate cancer (CRPC). Median time to CRPC was 20 m (range 16.9-23.1) and median OS was not reached. High AR-signature expression independently correlated with longer CRPC-FS (HR 0.4, 95% CI 0.2-0.7, p = 0.003). Considering AR-signature individual gene expression, ARV7 was independently associated with shorter CRPC-FS (HR 1.7, 95% CI 1.2-2.4, p = 0.003). Low expression of all TSG ( PTEN, RB1 and TP53) independently correlated with shorter CRPC-FS (HR 0.3, 95% CI 0.2-0.7, p = 0.003) and OS (HR 0.2, 95% CI 0.1-0.5, p < 0.001). Similarly, low expression of 2 out of the 3 TSG genes or only RB1 plus PTEN were also independently associated with shorter CRPC-FS (HR 0.5, 95% CI 0.3-0.9, p = 0.015; HR 0.4, 95% CI 0.2-0.7, p = 0.003, respectively) and OS (HR 0.4, 95% CI 0.2-0.9, p = 0.027; HR 0.2, 95% CI 0.1-0.6, p = 0.001, respectively). TMPRSS2-ERG expression, NE, EMT and immune-related signatures were not associated with clinical outcome. Bujar analysis defined a 17-gene signature (including ARV7, RB1, PTEN, BRCA2 and ATM) that was able to discriminate pts at different risk of developing early CRPC. Conclusions: High AR-signature expression correlates with a longer CRPC-FS while ARV7 expression is associated with shorter CRPC-FS. Low expression of TSG is associated with an aggressive clinical evolution in mHSPC pts treated with ADT+taxanes.

Response factors associated with electrocautery treatment of intra-anal high-grade squamous intraepithelial lesions in a population of HIV-positive men who have sex with men

BACKGROUND

Ablative treatment of anal high-grade squamous intraepithelial lesions (HSIL) reduces the risk of progression to anal squamous cell carcinoma.

OBJECTIVES

To identify factors that influence the response to treatment of anal HSIL by electrocautery ablation (ECA) in a population of HIV-positive men who have sex with men (MSM).

DESIGN

Retrospective study of ECA treatment response in a prospectively followed anal dysplasia cohort. HIV-positive MSM diagnosed with anal HSIL were included. Demographic and HIV data were recorded. Response to treatment was assessed by biopsy after at least 18 months of follow-up.

RESULTS

One hundred and twenty-eight HSILs in 91 men were included in this study. The overall response rate at 18 months was 70.3%. The number of electrocautery sessions required (2 ECA sessions vs 1: adjusted odds ratio [aOR] = 0.36 (95%CI 0.13-1.01); >=3 sessions vs 1: aOR = 0.10 (95%CI 0.04-0.29); p < 0.001]) and the history of previous HPV-related anal pathology (previous anal lesions vs no previous lesions AOR = 2.83 (95%CI 1.14-7.02), p = 0.024) were independently associated with response at 18 months. No serious adverse events were reported.

CONCLUSIONS

Consideration should be given to alternative therapies in patients with unresolved HSIL after 1 ECA treatment.

Effect of vascularized periosteum on revitalization of massive bone isografts: An experimental study in a rabbit model

INTRODUCTION

In the last years, limb salvage has become the gold standard treatment over amputation. Today, 90% of extremity osteogenic sarcomas can be treated with limb salvage surgery. However, these reconstructions are not exempt from complications. Massive allografts have been associated to high risk of nonunion (12-57%), fracture (7-30%) and infection (5-21%). Association of vascularized periosteum flap to a massive bone allograft (MBA) has shown to halve the average time of allograft union in clinical series, even compared to vascularized fibular flap. Creeping substitution process has been reported in massive allograft when periosteum flap was associated. However, we have little data about whether it results into allograft revitalization. We hypothesize that the association of a periosteum flap to a bone isograft promotes isograft revitalization, defined as the colonization of the devitalized bone by new-form vessels and viable osteocytes, turning it vital.

MATERIALS AND METHODS

Forty-four New Zealand white male rabbits underwent a 10 mm segmental radial bone defect. In 24 rabbits the bone excision included the periosteum (controls); in 20 rabbits (periosteum group) bone excision was performed carefully detaching periosteum in order to preserve it. Cryopreserved bone isograft from another rabbit was trimmed and placed to the defect gap and was fixed with a retrograde intramedullar 0.6 mm Kirschner wire. Rabbits were randomized and distributed in 3 subgroups depending on the follow-up (control group: 5 rabbits in 5-week follow up group, 8 rabbits in 10-week follow-up group, 7 rabbits in 20-week follow-up group; periosteum group: 5 rabbits in 5-week follow up group, 7 rabbits in 10-week follow-up group, 7 rabbits in 20-week follow-up group). Fluoroscopic images of rabbit forelimb were taken after sacrifice to address union. Each specimen was blindly evaluated in optical microscope (magnification, ×4) after hematoxylin and eosin staining to qualitative record: presence of new vessels and osteocytes in bone graft lacunae (yes/no) to address revitalization, presence of callus (yes/no) and woven bone and cartilage tissue area (mm2 ) to address remodeling (osteoclast resorption of old bone and substitution by osteoblastic new bone formation).

RESULTS

No isograft revitalization occurred in any group, but it was observed bone graft resorption and substitution by new-formed bone in periosteum group. This phenomenon was accelerated in 5-week periosteum group (control group: 49.5 ± 9.6 mm2 vs. periosteum group: 34.9 ± 10.4 mm2 ; p = .07). Remodeled lamellar bone was observed in both 20-week groups (control group: 6.1 ± 6.3 mm2 vs. periosteum group: 5.8 ± 3.0 mm2 , p = .67). Periosteum group showed complete integration and graft substitution, whereas devitalized osteons were still observed in 20-week controls. All periosteum group samples showed radiographic union through a bone callus, whereas controls showed nonunion in eight specimens (Union rate: control group 60% vs. periosteum group 100%, p = .003).

CONCLUSIONS

Association of vascularized periosteum to a massive bone isograft has shown to accelerate bone graft substitution into a newly formed bone, thus, no bone graft revitalization occurs.

Molecular classification and therapeutic targets in extrahepatic cholangiocarcinoma

BACKGROUND & AIMS

Cholangiocarcinoma (CCA), a deadly malignancy of the bile ducts, can be classified based on its anatomical location into either intrahepatic (iCCA) or extrahepatic (eCCA), each with different pathogenesis and clinical management. There is limited understanding of the molecular landscape of eCCA and no targeted therapy with clinical efficacy has been approved. We aimed to provide a molecular classification of eCCA and identify potential targets for molecular therapies.

METHODS

An integrative genomic analysis of an international multicenter cohort of 189 eCCA cases was conducted. Genomic analysis included whole-genome expression, targeted DNA-sequencing and immunohistochemistry. Molecular findings were validated in an external set of 181 biliary tract tumors from the ICGC.

RESULTS

KRAS (36.7%), TP53 (34.7%), ARID1A (14%) and SMAD4 (10.7%) were the most prevalent mutations, with ∼25% of tumors having a putative actionable genomic alteration according to OncoKB. Transcriptome-based unsupervised clustering helped us define 4 molecular classes of eCCA. Tumors classified within the Metabolic class (19%) showed a hepatocyte-like phenotype with activation of the transcription factor HNF4A and enrichment in gene signatures related to bile acid metabolism. The Proliferation class (23%), more common in patients with distal CCA, was characterized by enrichment of MYC targets, ERBB2 mutations/amplifications and activation of mTOR signaling. The Mesenchymal class (47%) was defined by signatures of epithelial-mesenchymal transition, aberrant TGFβ signaling and poor overall survival. Finally, tumors in the Immune class (11%) had a higher lymphocyte infiltration, overexpression of PD-1/PD-L1 and molecular features associated with a better response to immune checkpoint inhibitors.

CONCLUSION

An integrative molecular characterization identified distinct subclasses of eCCA. Genomic traits of each class provide the rationale for exploring patient stratification and novel therapeutic approaches.

LAY SUMMARY

Targeted therapies have not been approved for the treatment of extrahepatic cholangiocarcinoma. We performed a multi-platform molecular characterization of this tumor in a cohort of 189 patients. These analyses revealed 4 novel transcriptome-based molecular classes of extrahepatic cholangiocarcinoma and identified ∼25% of tumors with actionable genomic alterations, which has potential prognostic and therapeutic implications.

Association of neuroendocrine (NE) mRNA expression profiling in hormone-sensitive tumors samples with adverse clinical outcome in castration-resistant prostate cancer (CRPC) patients

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Background: NE dedifferentiation is associated to clinical aggressiveness and resistance to androgen receptor inhibition in prostate cancer. We investigated impact of a NE expression signature in the clinical outcome of mCRPC patients treated with taxanes. Methods: This is a multicenter retrospective study. A customized panel of 45 NE-related gene signature was tested in total RNA from formalin-fixed paraffin-embedded hormone-sensitive tumor samples, by the nCounter platform (Nanostring Technologies). Patients were grouped according to their molecular profile by unsupervised clustering. Expression levels were correlated with taxanes response and clinical outcome. Independent association with survival was evaluated by multivariate Cox modeling. Results: Eighty seven patients were included in the study, 79 were treated with docetaxel and 8 with cabazitaxel. Median age was 64.8 (44-88.3) years and median follow-up was 20.7 (1.17-74.4) months. High expression of the NE signature was associated with a shorter time of CRPC development (N=60, median 12.8 vs 21.6, HR 2.4, 95%CI 1.3-4.3, P=0.003) and shorter OS from CRPC diagnosis (median 24.1 vs 41.33, HR 2.3, 95%CI 1.4-3.8, P=0.001). Moreover, according to the outcome to taxanes, high NE signature correlated with lower PSA-PFS (median 6.6 vs 10.1 mo P=0.047, HR 1.6, 95%CI 1-2.7, P=0.05) and OS (median 19 vs 22 mo, HR 1.8, 95%CI 1.1-2.8, P=0.014), and it was independently associated to a lower OS (HR 1.9, 95%CI 1.1-3.2, P=0.016). Conclusions: NE-related gene expression in hormone-sensitive tumor samples is associated with adverse clinical outcome and lower taxane benefit in metastatic CRPC patients. Thus, molecular characterization of primary tumors may be useful to guide treatment strategies in metastatic prostate cancer.

Response to immunotherapy, platinum-based chemotherapy or their combination in metastatic urothelial carcinoma (MUC) with or without FGFR-3 alterations: Single cohort experience

560

Background: Fibroblast growth factor receptor-3 (FGFR-3) is a promising target therapy in metastatic urothelial carcinoma. Its role in patient’s clinical outcome and treatment response is unclear. We present data for overall survival (OS) and response to platinum-based treatment, immunotherapy and combination (platinum plus immunotherapy) in MUC. Methods: Enrolled patients were diagnosed with muscle-invasive urothelial cancer (MIUC) between 2/2009-6/2019 at Clinic Hospital of Barcelona, Spain. All have been screened for FGFR-3 alterations using next-generation sequencing or qualitative real-time polymerase chain reaction-based assays in tumour or blood. Demographic, pathology, treatments and treatment response were collected retrospectively. Results: 101 patients with MIUC were screened, 99% had progressed to metastatic stage. At diagnosis 32.67% were metastatic. 77% were man and median age was 68y (38-85y). Median follow-up (FU) since metastatic disease was 16.25 months (1.2-89.72m) with 69.31% of patients had died at cut-off. 32% presented FGFR-3 alteration (fusion =1 and mutation=31). FGFR-3 altered more frequently had papillary histology than FGFR-3 wild type tumours (69 vs 26%, p<0.05). No statistical differences were detected between both groups for gender, age, stage at diagnosis, median FU, primary tumour site (upper vs lower tract) or previous history of non-invasive urothelial carcinoma. 58% patients received 1st line platinum-based chemotherapy, 25% immunotherapy and 8% the combination of both (9% with other therapies). FGFR-3 altered tended to present more benefit (complete, partial response or stable disease) with platinum-based chemotherapy than FGFR-3 wild type (81% vs 62%) but without reach statistical significance. No differences were detected for immunotherapy or combination therapies. Moreover, OS was similar for FGFR-3 altered (median 14.6m) and FGFR-3 wild- type (median 17.1 m) (HR 0.76, p=0.3). Conclusions: In our series, no significant differences related to response to first line therapy or survival was observed.

Molecular predictors of prevention of recurrence in HCC with sorafenib as adjuvant treatment and prognostic factors in the phase 3 STORM trial

OBJECTIVE

Sorafenib is the standard systemic therapy for advanced hepatocellular carcinoma (HCC). Survival benefits of resection/local ablation for early HCC are compromised by 70% 5-year recurrence rates. The phase 3 STORM trial comparing sorafenib with placebo as adjuvant treatment did not achieve its primary endpoint of improving recurrence-free survival (RFS). The biomarker companion study BIOSTORM aims to define (A) predictors of recurrence prevention with sorafenib and (B) prognostic factors with B level of evidence.

DESIGN

Tumour tissue from 188 patients randomised to receive sorafenib (83) or placebo (105) in the STORM trial was collected. Analyses included gene expression profiling, targeted exome sequencing (19 known oncodrivers), immunohistochemistry (pERK, pVEGFR2, Ki67), fluorescence in situ hybridisation (VEGFA) and immunome. A gene signature capturing improved RFS in sorafenib-treated patients was generated. All 70 RFS events were recurrences, thus time to recurrence equalled RFS. Predictive and prognostic value was assessed using Cox regression models and interaction test.

RESULTS

BIOSTORM recapitulates clinicopathological characteristics of STORM. None of the biomarkers tested (related to angiogenesis and proliferation) or previously proposed gene signatures, or mutations predicted sorafenib benefit or recurrence. A newly generated 146-gene signature identifying 30% of patients captured benefit to sorafenib in terms of RFS (p of interaction=0.04). These sorafenib RFS responders were significantly enriched in CD4+ T, B and cytolytic natural killer cells, and lacked activated adaptive immune components. Hepatocytic pERK (HR=2.41; p=0.012) and microvascular invasion (HR=2.09; p=0.017) were independent prognostic factors.

CONCLUSION

In BIOSTORM, only hepatocytic pERK and microvascular invasion predicted poor RFS. No mutation, gene amplification or previously proposed gene signatures predicted sorafenib benefit. A newly generated multigene signature associated with improved RFS on sorafenib warrants further validation.

TRIAL REGISTRATION NUMBER

NCT00692770.

IGF2 Is Up-regulated by Epigenetic Mechanisms in Hepatocellular Carcinomas and Is an Actionable Oncogene Product in Experimental Models

BACKGROUND & AIMS

Effective treatments are urgently needed for hepatocellular carcinoma (HCC), which is usually diagnosed at advanced stages. Signaling via the insulin-like growth factor (IGF) pathway is aberrantly activated in HCC by IGF2 overexpression. We aimed to elucidate the mechanism of IGF2 overexpression and its oncogenic activities and evaluate the anti-tumor effects of reducing IGF2 signaling.

METHODS

We obtained 228 HCC samples from patients who underwent liver resection, 168 paired non-tumor adjacent cirrhotic liver samples, and 10 non-tumor liver tissues from patients undergoing resection for hepatic hemangioma. We analyzed gene expression, microRNA, and DNA methylation profiles for all samples, focusing on genes in the IGF signaling pathway. IGF2 was expressed in SNU449 and PLC5 HCC cells and knocked down with small hairpin RNAs in Hep3B and Huh7 cell lines. We analyzed these cells for proliferation, apoptosis, migration, and colony formation. We performed studies in mice engineered to express Myc and Akt1 in liver, which develop liver tumors, with or without hepatic expression of Igf2. Mice with xenograft tumors grown from HCC cells were given a monoclonal antibody against IGF1 and IGF2 (xentuzumab), along with sorafenib; tumor growth was measured and tissues were analyzed by immunohistochemistry and immunoblots.

RESULTS

Levels of IGF2 messenger RNA and protein were increased >20-fold in 15% of human HCC tissues compared with non-tumor liver tissues. Methylation at the fetal promoters of IGF2 was reduced in the HCC samples and cell lines that overexpressed IGF2, compared with those that did not overexpress this gene, and non-tumor tissues. Tumors that overexpressed IGF2 had gene expression patterns significantly associated with hepatic progenitor cell features, stellate cell activation, NOTCH signaling, and an aggressive phenotype (P < .0001). In mice engineered to express Myc and Akt1 in liver, co-expression of Igf2 accelerated formation of liver tumors, compared to mice with livers expressing only Myc and Akt1, and shortened survival times (P = .02). The antibody xentuzumab blocked phosphorylation of IGF1 receptor in HCC cell lines and reduced their proliferation and colony formation. In mice with xenograft tumors, injection of xentuzumab, with or without sorafenib, slowed tumor growth and increased survival times compared to vehicle or sorafenib alone. Xentuzumab inhibited phosphorylation of IGF1 receptor and AKT and reduced decreased tumor vascularization compared with vehicle.

CONCLUSIONS

A large proportion of HCC samples were found to overexpress IGF2, via demethylation of its fetal promoter. Overexpression of IGF2 accelerates formation of liver tumors in mice with hepatic expression of MYC and AKT1, via activation of IGF1 receptor signaling. An antibody against IGF1 and IGF2 slows growth of xenograft tumors and increases survival of these mice.

Unique genomic profile of fibrolamellar hepatocellular carcinoma

BACKGROUND & AIMS

Fibrolamellar hepatocellular carcinoma (FLC) is a rare primary hepatic cancer that develops in children and young adults without cirrhosis. Little is known about its pathogenesis, and it can be treated only with surgery. We performed an integrative genomic analysis of a large series of patients with FLC to identify associated genetic factors.

METHODS

By using 78 clinically annotated FLC samples, we performed whole-transcriptome (n = 58), single-nucleotide polymorphism array (n = 41), and next-generation sequencing (n = 48) analyses; we also assessed the prevalence of the DNAJB1-PRKACA fusion transcript associated with this cancer (n = 73). We performed class discovery using non-negative matrix factorization, and functional annotation using gene-set enrichment analyses, nearest template prediction, ingenuity pathway analyses, and immunohistochemistry. The genomic identification of significant targets in a cancer algorithm was used to identify chromosomal aberrations, MuTect and VarScan2 were used to identify somatic mutations, and the random survival forest was used to determine patient prognoses. Findings were validated in an independent cohort.

RESULTS

Unsupervised gene expression clustering showed 3 robust molecular classes of tumors: the proliferation class (51% of samples) had altered expression of genes that regulate proliferation and mammalian target of rapamycin signaling activation; the inflammation class (26% of samples) had altered expression of genes that regulate inflammation and cytokine enriched production; and the unannotated class (23% of samples) had a gene expression signature that was not associated previously with liver tumors. Expression of genes that regulate neuroendocrine function, as well as histologic markers of cholangiocytes and hepatocytes, were detected in all 3 classes. FLCs had few copy number variations; the most frequent were focal amplification at 8q24.3 (in 12.5% of samples), and deletions at 19p13 (in 28% of samples) and 22q13.32 (in 25% of samples). The DNAJB1-PRKACA fusion transcript was detected in 79% of samples. FLC samples also contained mutations in cancer-related genes such as BRCA2 (in 4.2% of samples), which are uncommon in liver neoplasms. However, FLCs did not contain mutations most commonly detected in liver cancers. We identified an 8-gene signature that predicted survival of patients with FLC.

CONCLUSIONS

In a genomic analysis of 78 FLC samples, we identified 3 classes based on gene expression profiles. FLCs contain mutations and chromosomal aberrations not previously associated with liver cancer, and almost 80% contain the DNAJB1-PRKACA fusion transcript. By using this information, we identified a gene signature that is associated with patient survival time.

Notch signaling is activated in human hepatocellular carcinoma and induces tumor formation in mice

BACKGROUND & AIMS

The Notch signaling pathway is activated in leukemia and solid tumors (such as lung cancer), but little is known about its role in liver cancer.

METHODS

The intracellular domain of Notch was conditionally expressed in hepatoblasts and their progeny (hepatocytes and cholangiocytes) in mice. This was achieved through Cre expression under the control of an albumin and α-fetoprotein (AFP) enhancer and promoter (AFP-Notch intracellular domain [NICD]). We used comparative functional genomics to integrate transcriptome data from AFP-NICD mice and human hepatocellular carcinoma (HCC) samples (n = 683). A Notch gene signature was generated using the nearest template prediction method.

RESULTS

AFP-NICD mice developed HCC with 100% penetrance when they were 12 months old. Activation of Notch signaling correlated with activation of 3 promoters of insulin-like growth factor 2; these processes appeared to contribute to hepatocarcinogenesis. Comparative functional genomic analysis identified a signature of Notch activation in 30% of HCC samples from patients. These samples had altered expression in Notch pathway genes and activation of insulin-like growth factor signaling, despite a low frequency of mutations in regions of NOTCH1 associated with cancer. Blocking Notch signaling in liver cancer cells with the Notch activation signature using γ-secretase inhibitors or by expressing a dominant negative form of mastermind-like 1 reduced their proliferation in vitro.

CONCLUSIONS

Notch signaling is activated in human HCC samples and promotes formation of liver tumors in mice. The Notch signature is a biomarker of response to Notch inhibition in vitro.