Intravenous 6-mercaptopurine decreases salvage after relapse in childhood acute lymphoblastic leukemia: a report from the Children's Cancer Group study CCG 1922

Constitutional mismatch repair-deficiency: current problems and emerging therapeutic strategies

Mismatch repair (MMR) proteins remove errors from newly synthesized DNA, improving the fidelity of DNA replication. A loss of MMR causes a mutated phenotype leading to a predisposition to cancer. In the last 20 years, an increasing number of patients have been described with biallelic MMR gene mutations in which MMR defects are inherited from both parents. This leads to a syndrome with recessive inheritance, referred to as constitutional mismatch repair-deficiency (CMMRD). CMMRD is a rare childhood cancer predisposition syndrome. The spectrum of CMMRD tumours is broad and CMMRD-patients possess a high risk of multiple cancers including hematological, brain and intestinal tumors. The severity of CMMRD is highlighted by the fact that patients do not survive until later life, emphasising the requirement for new therapeutic interventions. Many tumors in CMMRD-patients are hypermutated leading to the production of truncated protein products termed neoantigens. Neoantigens are recognized as foreign by the immune system and induce antitumor immune responses. There is growing evidence to support the clinical efficacy of neoantigen based vaccines and immune checkpoint inhibitors (collectively referred to as immunotherapy) for the treatment of CMMRD cancers. In this review, we discuss the current knowledge of CMMRD, the advances in its diagnosis, and the emerging therapeutic strategies for CMMRD-cancers.

Everyday executive function in standard-risk acute lymphoblastic leukemia survivors

We aimed to evaluate parent-rated executive function (EF) in pediatric standard risk acute lymphoblastic leukemia (SR-ALL) survivors compared to a healthy comparison (HC) group. We hypothesized that SR-ALL survivors would have greater reported executive dysfunction compared to HC, and that those younger at the time of treatment would demonstrate greater EF difficulties. A sample of 256 SR-ALL survivors evaluated an average nine years after treatment were compared to HC matched for gender, assessment age, and maternal education. Profile analysis was used to compare the groups across EF scales on the BRIEF. The prevalence of clinical elevations in the groups was compared via chi square, and odds ratios were calculated. Regression models were applied to examine the role of age at diagnosis and age at assessment in reported EF. Results indicated that SR-ALL survivors' mean scores of EF are similar to HC, except for flexibility and initiation. Survivors were rated as having clinical impairments with flexibility, initiation, working memory, and emotional control at rates two to three times that of HC. The risk of working memory and self-monitoring deficits was greater in survivors who were older when assessed. There was no relationship between age at diagnosis or treatment regimen on EF. These findings suggest sparing of extensive and severe EF deficits in SR-ALL survivors overall. However, a subset of survivors displays clinically significant executive dysfunction. There appears to be a heightened susceptibility to disrupted metacognitive functions as survivors age. This has implications for how we monitor neurocognitive development and functioning of SR-ALL survivors, and highlights opportunities for cognitive interventions.

Postrelapse survival in childhood acute lymphoblastic leukemia is independent of initial treatment intensity: a report from the Children's Oncology Group

While intensification of therapy has improved event-free survival (EFS) and survival in newly diagnosed children with acute lymphoblastic leukemia (ALL), postrelapse outcomes remain poor. It might be expected that patients relapsing after inferior initial therapy would have a higher retrieval rate than after superior therapy. In the Children's Oncology Group Study CCG-1961, significantly superior EFS and survival were achieved with an augmented (stronger) versus standard intensity regimen of postinduction intensification (PII) for children with newly diagnosed high-risk ALL and rapid day 7 marrow response (EFS/survival 81.2%/88.7% vs 71.7%/83.4%, respectively). This provided an opportunity to evaluate postrelapse survival (PRS) in 272 relapsed patients who had received randomly allocated initial treatment with augmented or standard intensity PII. As expected, PRS was worse for early versus late relapse, marrow versus extramedullary site, adolescent versus younger age and T versus B lineage. However, no difference in 3-year PRS was detected for having received augmented versus standard intensity PII (36.4% ± 5.7% vs 39.2% ± 4.1%; log rank P = .72). Similar findings were noted within subanalyses by timing and site of relapse, age, and immunophenotype. These findings provide insight into mechanisms of relapse in ALL, and are consistent with emergence of a resistant subclone that has acquired spontaneous mutations largely independent of initial therapy. This study is registered at www.clinicaltrials.gov as NCT00002812.