Highly rearranged and mutated cancer genomes present major challenges in the identification of pathogenetic events driving the neoplastic transformation process. Here we engineered lymphoma-prone mice with chromosomal instability to assess the usefulness of mouse models in cancer gene discovery and the extent of cross-species overlap in cancer-associated copy number aberrations. Along with targeted re-sequencing, our comparative oncogenomic studies identified FBXW7 and PTEN to be commonly deleted both in murine lymphomas and in human T-cell acute lymphoblastic leukaemia/lymphoma (T-ALL). The murine cancers acquire widespread recurrent amplifications and deletions targeting loci syntenic to those not only in human T-ALL but also in diverse human haematopoietic, mesenchymal and epithelial tumours. These results indicate that murine and human tumours experience common biological processes driven by orthologous genetic events in their malignant evolution. The highly concordant nature of genomic events encourages the use of genomically unstable murine cancer models in the discovery of biological driver events in the human oncogenome.

Patients with IHH are almost invariably either anosmic (KS) or normosmic (nIHH), rather than exhibiting intermediate degrees of olfactory deficit. Moreover, the prevalence of cryptorchidism is nearly three times greater in KS than in nIHH despite comparable testicular volumes, suggesting a primary defect of testicular descent in KS independent of gonadotrophin deficiency. Disorders of eye movement and hearing appear only to occur in association with KS. Taken together, these findings indicate a clear phenotypic separation between KS and nIHH. However, pedigree studies suggest that autosomal KS is an heterogeneous condition, with incomplete phenotypic penetrance within pedigrees, and that some cases of autosomal KS, nIHH and even isolated anosmia are likely to have a common genetic basis. The prevalences of anosmia, mirror movements and unilateral renal agenesis among X-KS men are estimated to be 100, 85 and 31%, respectively. In sporadic IHH, mirror movements and unilateral renal agenesis are 100% specific phenotypic markers of de novo X-KS. By comparison, only 7/10 X-KS families harboured KAL coding defects. Clinical ascertainment, using mirror movements, renal agenesis and ichthyosis as X-KS-specific phenotypic markers, suggested that de novo X-KS was unlikely to comprise more than 11% of sporadic cases. The majority of sporadic KS cases are therefore presumed to have an autosomal basis and, hence, the preponderance of affected KS males over females remains unexplained, though reduced penetrance in women would be a possibility.

A detailed neurological investigation of patients with Kallmann's syndrome (KS) has been performed in an attempt to relate phenotypic characterization with genotype. Twenty-seven subjects with KS were studied (including 12 males with X-linked disease and 3 females). Six male and 2 female normosmics with isolated GnRH deficiency, 1 male with KS variant, and 1 obligate female carrier were also imaged. Evidence for X-linked disease was derived both from analysis of pedigree and by mutation analysis at the KAL locus. The female carrier and all 8 normosmics had normal olfactory bulbs and sulci, as did 3 male KS. The study, therefore, confirms the value of magnetic resonance imaging in the diagnosis of KS, but suggests that the technique is not sufficiently sensitive to differentiate KS from the normosmic form of GnRH deficiency in all cases. Phenotypic characterization of KS was more effectively achieved by accurate estimation of olfactory status. Three new mutations at the KAL locus were identified, 2 single exon deletions and 1 point mutation. In 2 pedigrees with clear X-linked inheritance, no coding sequence mutations were detected; it may be that these harbor mutations of pKAL, the recently characterized 5'-promoter region. No clear relationship could be established between specific phenotypic anomalies and particular KAL mutations. Involuntary, mirror movements of the upper limbs were present in 10 of 12 cases of X-linked KS, but in none of the other subjects. Although this phenomenon has been ascribed to an abnormality of the corpus callosum, in the present study magnetic resonance imaging demonstrated no quantitative or qualitative morphological anomalies of this structure.

Summary The predictive value of molecular minimal residual disease (MRD) monitoring using polymerase chain reaction amplification of clone‐specific immunoglobulin or T‐cell Receptor rearrangements was analysed in 161 patients with non T‐lineage Philadelphia‐negative acute lymphoblastic leukaemia (ALL) participating in the UK arm of the international ALL trial UKALL XII/Eastern Cooperative Oncology Group (ECOG) 2993. MRD positivity (≥10−4) in patients treated with chemotherapy alone was associated with significantly shorter relapse‐free survival (RFS) at several time‐points during the first year of therapy. MRD status best discriminated outcome after phase 2 induction, when the relative risk of relapse was 8·95 (2·85–28·09)‐fold higher in MRD‐positive (≥10−4) patients and the 5‐year RFS 15% [95% confidence interval (CI) 0–40%] compared to 71% (56–85%) in MRD‐negative (<10−4) patients (P = 0·0002) When MRD was detected prior to autologous stem cell transplantation (SCT), a significantly higher rate of treatment failure was observed [5‐year RFS 25% (CI 0–55%) vs. 77% (95% CI 54–100%) in MRD‐negative/<10−4, P = 0·01] whereas in recipients of allogeneic‐SCT in first complete remission, MRD positivity pre‐transplant did not adversely affect outcome. These data provide a rationale for introducing MRD‐based risk stratification in future studies for the delineation of those at significant risk of treatment failure in whom intensification of therapy should be evaluated.