TOP3A amplification and ATRX inactivation are mutually exclusive events in pediatric osteosarcomas using ALT.

In some types of cancer, telomere length is maintained by the alternative lengthening of telomeres (ALT) mechanism. In many ALT cancers, the α-thalassemia/mental retardation syndrome X-linked (ATRX) gene is mutated leading to the conclusion that the ATRX complex represses ALT. Here, we report that most high-grade pediatric osteosarcomas maintain their telomeres by ALT, and that the majority of these ALT tumors are ATRX wild-type (wt) and instead carry an amplified 17p11.2 chromosomal region containing TOP3A. We found that TOP3A was overexpressed in the ALT-positive ATRX-wt tumors consistent with its amplification. We demonstrated the functional significance of these results by showing that TOP3A overexpression in ALT cancer cells countered ATRX-mediated ALT inhibition and that TOP3A knockdown disrupted the ALT phenotype in ATRX-wt cells. Moreover, we report that TOP3A is required for proper BLM localization and promotes ALT DNA synthesis in ALT cell lines. Collectively, our results identify TOP3A as a major ALT player and potential therapeutic target.

Treatment of 120 adult osteosarcoma patients with metachronous and synchronous metastases: A retrospective series of the French Sarcoma Group.

Treatment options for metastatic osteosarcomas are scarce. Following failure of standard first line therapy, patients who relapse present a challenging treatment dilemma, and have a poor prognosis. Surgical removal of all metastases is essential. A retrospective analysis of patients with metastatic osteosarcomas was conducted in 15 French Sarcoma Group centers. From January 2009 to December 2018, we identified 120 adult patients; 36 with synchronous and 84 with metachronous metastases with 74 males and 46 females. Mean age was 30 years (18-53). Metastatic sites were lung, bone and other in 91, 11 and 24 patients, respectively. Mean time to first metachronous metastases was 22 months (4-97). All patients except 13 (10.8%) with metachronous metastases received a first line systemic treatment for relapse, and 39 patients (32.5%) were included in a clinical trial. Eighty-one patients (67.5%) had local treatment of distant metastases. Median progression free survival (PFS) and overall survival (OS) were 5.5 (95% CI 4.6-6.4) and 20.5 months (95% CI 13.2-27.7) respectively for the overall group. In multivariate analysis, more than five metastases, time to first metastases <24 months, were statistically significant negative prognostic factors for OS and PFS (P = .002, ≤.001 and P = .006, ≤.001, respectively). Surgery of metastases was associated with better prognosis on OS and PFS (P = .001 and .037, respectively). The presence of bone metastases was a negative prognostic factor on OS but not on PFS (P = .021). In reference sarcoma centers, relapsed osteosarcoma patients with more than one metastasis commonly receive more than one line of systemic therapy, and are included in clinical trial if available.

Ovarian cancer patients at high risk of BRCA mutation: the constitutional genetic characterization does not change prognosis.

Ovarian neoplasms secondary to germline BRCA mutations had been described to have a more favourable survival. There is only few data concerning the prognosis of non mutated patients presenting clinical features evocative of BRCA alterations. We retrospectively collected data from patients treated in our institution for an invasive ovarian carcinoma between 1995 and 2011. Patients considered at high risk of BRCA mutation were tested for BRCA1/2 germline mutations. We described clinical, pathological and therapeutic features and compared prognosis of BRCA mutation carriers and non-mutated patients. Out of 617 ovarian cancer patients, we identified 104 patients who were considered at high risk of mutation. The 33 mutated patients were more likely to present a personal (33 vs. 10 %, p = 0.003) or a family (42 vs. 24 %, p = 0.06) history of breast/ovarian cancers. BRCA1/2 mutation carriers and wild type patients displayed similar prognosis: median progression-free survival (PFS) of 20.9 versus 37.7 months (p = 0.21); median overall survival (OS) of 151.2 versus 122.5 months (p = 0.52). Personal history of breast cancer increased both PFS [HR = 0.45 (95CI 0.25-0.81)] and OS [HR = 0.35 (95CI 0.16-0.75)]. In multivariate analysis, this parameter was an independent prognostic feature, whereas the identification of a BRCA1/2 mutation was not. In our cohort, all patients at high risk of BRCA mutation share a similar prognosis, whatever is their germline mutation status. Prognosis seems to be more influenced by clinical history than by germline mutations identification. If it is confirmed in larger and independent series, this result suggests that the hypothesis of other BRCA pathway alterations (BRCAness phenotype) deserves to be deeply explored.