Multidisciplinary consensus on optimising the detection of NTRK gene alterations in tumours

The recent identification of rearrangements of neurotrophic tyrosine receptor kinase (NTRK) genes and the development of specific fusion protein inhibitors, such as larotrectinib and entrectinib, have revolutionised the diagnostic and clinical management of patients presenting with tumours with these alterations. Tumours that harbour NTRK fusions are found in both adults and children; and they are either rare tumours with common NTRK fusions that may be diagnostic, or more prevalent tumours with rare NTRK fusions. To assess currently available evidence on this matter, three key Spanish medical societies (the Spanish Society of Medical Oncology (SEOM), the Spanish Society of Pathological Anatomy (SEAP), and the Spanish Society of Paediatric Haematology and Oncology (SEHOP) have brought together a group of experts to develop a consensus document that includes guidelines on the diagnostic, clinical, and therapeutic aspects of NTRK-fusion tumours. This document also discusses the challenges related to the routine detection of these genetic alterations in a mostly public Health Care System.

Selective modulation by PARP-1 of HIF-1α-recruitment to chromatin during hypoxia is required for tumor adaptation to hypoxic conditions

BACKGROUND

The adaptation to hypoxia is mainly controlled by the HIF transcription factors. Increased expression/activity of HIF-1α correlates with poor prognosis in cancer patients. PARP-1 inhibitors are used in the clinic to treat BRCAness breast/ovarian cancer and have been shown to regulate the hypoxic response; therefore, their use could be expanded.

METHODS

In this work by integrating molecular/cell biology approaches, genome-wide ChIP-seq, and patient samples, we elucidate the extent to which PARP-1 exerts control over HIF-1-regulated genes.

RESULTS

In human melanoma, PARP-1 and HIF-1α expression are strongly associated. In response to a hypoxic challenge poly(ADP-ribose) (PAR) is synthesized, HIF-1α is post-transcriptionally modified (PTM) and stabilized by PARylation at specific K/R residues located at its C-terminus. Using an unbiased ChIP-seq approach we demonstrate that PARP-1 dictates hypoxia-dependent HIF-recruitment to chromatin in a range of HIF-regulated genes while analysis of HIF-binding motifs (RCGTG) reveals a restriction on the recognition of hypoxia responsive elements in the absence of PARP-1. Consequently, the cells are poorly adapted to hypoxia, showing a reduced fitness during hypoxic induction.

CONCLUSIONS

These data characterize the fine-tuning regulation by PARP-1/PARylation of HIF activation and suggest that PARP inhibitors might have therapeutic potential against cancer types displaying HIF-1α over-activation.

Correction to: Liquid biopsy in oncology: a consensus statement of the Spanish Society of Pathology and the Spanish Society of Medical Oncology

The article Liquid biopsy in oncology.

1q gain and CDT2 overexpression underlie an aggressive and highly proliferative form of Ewing sarcoma

Despite extensive characterization of the role of the EWS-ETS fusions, little is known about secondary genetic alterations and their clinical contribution to Ewing sarcoma (ES). It has been demonstrated that the molecular structure of EWS-ETS lacks prognostic value. Moreover, CDKN2A deletion and TP53 mutation, despite carrying a poor prognosis, are infrequent. In this scenario identifying secondary genetic alterations with a significant prevalence could contribute to understand the molecular mechanisms underlying the most aggressive forms of ES.We screened a 67 ES tumor set for copy number alterations by array comparative genomic hybridization. 1q gain (1qG), detected in 31% of tumor samples, was found markedly associated with relapse and poor overall and disease-free survival and demonstrated a prognostic value independent of classical clinical parameters. Reanalysis of an expression dataset belonging to an independent tumor set (n=37) not only validated this finding but also led us to identify a transcriptomic profile of severe cell cycle deregulation in 1qG ES tumors. Consistently, a higher proliferation rate was detected in this tumor subset by Ki-67 immunohistochemistry. CDT2, a 1q-located candidate gene encoding a protein involved in ubiquitin ligase activity and significantly overexpressed in 1qG ES tumors, was validated in vitro and in vivo proving its major contribution to this molecular and clinical phenotype. This integrative genomic study of 105 ES tumors in overall renders the potential value of 1qG and CDT2 overexpression as prognostic biomarkers and also affords a rationale for the application of already available new therapeutic compounds selectively targeting the protein-ubiquitin machinery.

Subgroup analysis of GEICAM 9906 trial comparing six cycles of FE90C (FEC) to four cycles of FE90C followed by 8 weekly paclitaxel administrations (FECP): Relevance of HER2 and hormonal status (HR)

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Background: GEICAM 9906 interim analysis showed FECP improved disease-free survival (DFS) compared to FEC (SABCS 2005, abstract #39). As a secondary objective, predictive markers were centrally determined and DFS of subgroups analyzed. A prior report from CALGB 9344 trial suggested that patients (pt) with HER2+ tumors get the maximum benefit with adjuvant P (ASCO 2006, abstract #510). We aimed to confirm this finding in our dataset. Methods: 1248 node + pt received 6 q3wk cycles (cy) of FEC (600/90/600 mg/m2) or 4 cy of same FEC followed by 8 wk cy of P (100 mg/m2). Tumor paraffin-embedded blocks were prospectively collected from 889 pt (71%) for Tissue Microarrays. Statistical analysis used Kaplan-Meier estimates for DFS by treatment group at a median follow-up (FU) of 65 months (m). HER2 status was evaluated by FISH. HR status was determined by IHC, following Allred criteria. Results: At a median of 65 m FU, DFS for FECP remains better than FEC (79% vs. 72%; p=0.0042; HR= 0.71). HER2: DFS for HER2+ and HER2- pt were 66% vs. 78% (p=0.0008; HR= 0.60). HER2+ subgroup (n=177): DFS with FECP and FEC were 63% vs. 70% [p=0.5187, HR=1.18 (0.71–1.98)]. HER2- subgroup (n=712): FECP was significantly better than FEC [82% vs. 74%, p=0.0075; HR=0.65 (0.48–0.89)]. HR: DFS for HR+ and HR- pt were 80% vs. 68% (p<0.0001; HR= 0.52). HR+ subgroup (n=561): DFS with FECP and FEC were 82% vs. 79%, [p=0.2162; HR=0.79 (0.54–1.15)]. HR- subgroup (n=311): DFS was 72% vs. 65% [p=0.1633, HR=0.76 (0.51–1.12)]. DFS data in the four HER2/HR subgroups is summarized in the table . Conclusions: FECP is superior to FEC mostly in HER2-HR- (triple negative) tumors. Our subgroup analysis does not support the superiority of the paclitaxel-containing arm (FECP) in pt with HER2 positive tumors.

[Table: see text]

[Table: see text]