A high-risk retinoblastoma subtype with stemness features, dedifferentiated cone states and neuronal/ganglion cell gene expression.

Retinoblastoma is the most frequent intraocular malignancy in children, originating from a maturing cone precursor in the developing retina. Little is known on the molecular basis underlying the biological and clinical behavior of this cancer. Here, using multi-omics data, we demonstrate the existence of two retinoblastoma subtypes. Subtype 1, of earlier onset, includes most of the heritable forms. It harbors few genetic alterations other than the initiating RB1 inactivation and corresponds to differentiated tumors expressing mature cone markers. By contrast, subtype 2 tumors harbor frequent recurrent genetic alterations including MYCN-amplification. They express markers of less differentiated cone together with neuronal/ganglion cell markers with marked inter- and intra-tumor heterogeneity. The cone dedifferentiation in subtype 2 is associated with stemness features including low immune and interferon response, E2F and MYC/MYCN activation and a higher propensity for metastasis. The recognition of these two subtypes, one maintaining a cone-differentiated state, and the other, more aggressive, associated with cone dedifferentiation and expression of neuronal markers, opens up important biological and clinical perspectives for retinoblastomas.

Multifunctional Natural Killer Cell Engagers Targeting NKp46 Trigger Protective Tumor Immunity.

Over the last decade, various new therapies have been developed to promote anti-tumor immunity. Despite interesting clinical results in hematological malignancies, the development of bispecific killer-cell-engager antibody formats directed against tumor cells and stimulating anti-tumor T cell immunity has proved challenging, mostly due to toxicity problems. We report here the generation of trifunctional natural killer (NK) cell engagers (NKCEs), targeting two activating receptors, NKp46 and CD16, on NK cells and a tumor antigen on cancer cells. Trifunctional NKCEs were more potent in vitro than clinical therapeutic antibodies targeting the same tumor antigen. They had similar in vivo pharmacokinetics to full IgG antibodies and no off-target effects and efficiently controlled tumor growth in mouse models of solid and invasive tumors. Trifunctional NKCEs thus constitute a new generation of molecules for fighting cancer. VIDEO ABSTRACT.

Hybrid oncocytic/chromophobe renal cell tumours do not display genomic features of chromophobe renal cell carcinomas.

Hybrid oncocytic/chromophobe tumours (HOCT) are renal tumours recently described displaying histological features of both renal oncocytoma (RO) and chromophobe renal cell carcinoma (ChRCC), raising the question of their precise signification in the RO/ChRCC group. This study aimed to describe clinicopathological features of so called HOCT and to characterise their genomic profile. Five hundred and eighty-three tumours belonging to the ChRCC/RO group were retrospectively reviewed. Twelve tumours that could not be classified as RO or CHRC were considered as HOCT. Hale staining and cytokeratin 7 (CK7) immunostaining were performed. Genomic profile was established by array comparative genomic hybridisation (array-CGH) on frozen samples. Mean age at diagnosis was 70 years (range 46-83). No recurrence was observed (median follow-up: 18 months; range 9-72). Tumour size ranged from 1 to 11 cm. HOCT showed an admixture of RO- and ChRCC-like areas and/or "hybrid" cells with overlapping cytonuclear and/or histochemical features. Hale staining was apical in 50 to 100 % of cells, and CK7 was expressed in 10 to 100 % of cells. Genomic profile was balanced in seven cases or showed a limited number of random imbalances in five cases, as observed in RO. In no instances were observed the characteristic chromosome losses of ChRCC. These results suggest that so called HOCT are not true hybrid tumours and rather could represent a morphological variant of RO. From a diagnostic perspective, an array-CGH analysis could be performed in ambiguous ChRCC/RO cases to formally exclude the diagnosis of ChRCC.

Choroidal melanoma: does endoresection prevent neovascular glaucoma in patient treated with proton beam irradiation?

PURPOSE: To evaluate the efficacy of endoresection after proton beam radiotherapy to prevent neovascular glaucoma (NVG) in patients treated for choroidal melanoma. METHODS: From a series of 4,867 patients treated for choroidal melanoma were prospectively recorded in the database (Macro Infermed 3.075). One hundred and seventy-one patients presenting a tumor diameter >10 mm and thickness >5 mm treated with proton beam (PB) radiotherapy were selected. One group of 63 patients was treated with PB therapy followed by endoresection (PE) of the scar. This group was compared with 2 historical matched controlled groups: 57 patients treated with PB therapy alone (P) and 51 patients treated with PB therapy followed by transpupillary thermotherapy of the scar (PTTT). Main outcome measures are as follows: age, gender, tumor diameter, tumor thickness, pre- and posttreatment visual acuity, NVG rate, secondary enucleation rate, and 5-year survival. Statistical analysis was performed using R version 2.5.1 software. RESULTS: Correlations between the 3 groups were P = 0.29 for age, P = 4.7×10 for tumor diameter, and P = 6.44×10 for tumor thickness. Comparison between the 3 groups showed that 2-year survival without secondary enucleation was 96.2% for PE, 88.8% for P, and 98% for PTTT (P = 0.203) (95% confidence interval). Two-year survival without NVG (95% confidence interval) was 92.7% (85.1-1.00) for PE, 54.6% for P, and 62.1% for PTTT (P = 0.0001). The difference between the endoresection (PE) group and the PB radiotherapy (P) and PB radiotherapy + TTT (PTTT) groups in terms of reduction of the NVG rate was statistically significant. Relative risk of developing NVG was calculated with the P group as reference, relative risk = 1. The relative risk of the PTTT group was 0.79 (20% reduction of the risk), and the relative risk of the PE group was 0.18 (82% reduction of the risk of developing NVG). CONCLUSION: This study shows that endoresection of the necrotic scar after PB radiotherapy reduces the risk of NVG and secondary enucleation for selected choroidal melanoma patients.

Conventional chondrosarcoma in a survivor of rhabdoid tumor: enlarging the spectrum of tumors associated with SMARCB1 germline mutations.

SMARCB1 germline mutations mainly predispose to rhabdoid tumors. However, less aggressive tumors with a later onset have also been reported in a context of SMARCB1 constitutional mutation-that is, schwannomatosis and meningiomatosis. No other tumor type has formally been observed in such a context thus far. We report on a patient treated for a thoracic malignant rhabdoid tumor at 8 years of age who subsequently developed a mandibular conventional chondrosarcoma at 13 years of age. Both tumors showed a loss of BAF47 expression. The malignant rhabdoid tumor exhibited a large 22q11.2 deletion and an intragenic deletion of SMARCB1 (exons 1 to 3), thus leading to a biallelic inactivation. A 2.8 Mbp deletion encompassing SMARCB1 was found in the germline. This context was a strong incentive to investigate SMARCB1 alterations in the second tumor. As expected, the chondrosarcoma showed the large 22q11.2 deletion but also an additional c.243C>G(p.Tyr18X) premature stop codon in the remaining allele. This report relates for the first time a pediatric conventional chondrosarcoma to the wide family of SMARCB1-deficient tumors. Moreover, we report here the first case of conventional chondrosarcoma arising in a context of constitutional SMARCB1 deletion and, thus, enlarge the spectrum of this tumor predisposition syndrome.