The most impactful clinical improvements in anticancer drugs have occurred with the debut of treatments with a novel mechanism of action. New classes of cytotoxic chemotherapy (anthracyclines or taxanes) led to notable clinical improvements in many tumor types. Imatinib in chronic myeloid leukemia was the first and arguably remains the best, so far, kinase inhibitor.¹ Monoclonal antibodies have provided major advances by targeting CD20 in B-lymphoma,² ERBB2-positive breast cancer,^3,4 and immune checkpoints.⁵

The concept of Cancer of Unknown Primary (CUP) has evolved with the advent of medical oncology. CUP can be difficult to diagnose and represents 2 to 5% of new cancers, therefore not exceptionally rare. Within CUPs can be identified a subset of favourable prognosis tumours, however the vast majority of CUP patients belongs to a poor prognosis group. CUP features significant oncological challenges, such as unravelling biological and transversal issues, and most importantly, improving patient's outcomes. In that regard, CUP patients' outcomes regrettably showed minimal improvement for decades and CUP remains a cancer group of very poor prognosis. The biology of CUP has two main hypotheses. One is that CUP is a subgroup of a given primary cancer, where the primary is present but cannot be seen due to its small size. The other, the "true" CUP hypothesis, states that CUP share features that make them a specific entity, whatever their tissue of origin. A true biological signature has not yet been described, but chromosomal instability is a hallmark of poor prognosis CUP group. Precision oncology, despite achieving identifying the putative origin of the CUP, so far failed to globally improve outcomes of patients. Targeting molecular pathways based on molecular analysis in CUP management is under investigation. Immunotherapy has not shown ground-breaking results, to date. Accrual is also a crucial issue in CUP trials. Herein we review CUP history, biological features and remaining questions in CUP biology, the two main approaches of molecular oncology in CUP management, in order to draw perspectives in the enormous challenge of improving CUP patient outcomes.

Purpose: BRCA2 plays a central role in homologous recombination by loading RAD51 on DNA breaks. The objective of this study is to determine whether the location of mutations in the RAD51-binding domain (RAD51-BD; exon 11) of BRCA2 gene affects the clinical outcome of ovarian cancer patients. Experimental Design: A study cohort of 353 women with ovarian cancer who underwent genetic germline testing for BRCA1 and BRCA2 genes was identified. Progression-free survival (PFS), platinum-free interval (PFI), and overall survival (OS) were analyzed. The Cancer Genome Atlas (TCGA) cohort of ovarian cancer (n = 316) was used as a validation cohort. Results: In the study cohort, 78 patients were carriers of germline mutations of BRCA2. After adjustment for FIGO stage and macroscopic residual disease, BRCA2 carriers with truncating mutations in the RAD51-BD have significantly prolonged 5-year PFS [58%; adjusted HR, 0.36; 95% confidence interval (CI), 0.20–0.64; P = 0.001] and prolonged PFI (29.7 vs. 15.5 months, P = 0.011), compared with noncarriers. BRCA2 carriers with mutations located in other domains of the gene do not have prolonged 5-year PFS (28%, adjusted HR, 0.67; 95% CI, 0.42–1.07; P = 0.094) or PFI (19 vs. 15.5 months, P = 0.146). In the TCGA cohort, only BRCA2 carriers harboring germline or somatic mutations in the RAD51-BD have prolonged 5-year PFS (46%; adjusted HR, 0.30; 95% CI, 0.13–0.68; P = 0.004) and 5-year OS (78%; adjusted HR, 0.09; 95% CI, 0.02–0.38; P = 0.001). Conclusions: Among ovarian cancer patients, BRCA2 carriers with mutations located in the RAD51-BD (exon 11) have prolonged PFS, PFI, and OS. Clin Cancer Res; 1–8. ©2017 AACR.

In recent years, several drugs underwent development only for individuals who have specific human leukocyte antigen (HLA) subtypes. These HLA subtypes are a protective mechanism that ensures the integrity of individuals (the self) against external threats (the nonself).^1-3 The HLA complex is composed of hundreds of highly polymorphic genes located on the short arm (p) of the sixth chromosome.^2-4 Given the unique role these molecules play in the immune system, some drugs have been engineered to bind to specific HLA constructs, and many more are in the pipeline. One drug, tebentafusp, a fusion protein targeting gp100, has received US Food and Drug Administration approval in advanced or metastatic uveal melanoma, only for patients positive for HLA-A*02:01.^5,6