Summary Deregulated HER2 is a target of many approved cancer drugs. We analyzed 111,176 patient tumors and identified recurrent HER2 transmembrane domain (TMD) and juxtamembrane domain (JMD) mutations, including G660D, R678Q, E693K and Q709L. Using a saturation mutagenesis screen and testing of patient-derived mutations we found several activating TMD and JMD mutations. Structural modeling and analysis showed that the TMD/JMD mutations function by improving the active dimer interface or stabilizing an activating conformation. Further, we found that HER2 G660D employed asymmetric kinase dimerization for activation and signaling. Importantly, anti-HER2 antibodies and small molecule kinase inhibitors blocked the activity of TMD/JMD mutants. Consistent with this, a G660D germline mutant lung cancer patient showed remarkable clinical response to HER2 blockade.

No abstract

The CR and EFS rates achieved represent a significant improvement over previous results at this institution. Bulky extramedullary disease was an important risk factor in this series, but age and WBC alone inadequately defined risk groups, suggesting that prognostic factors may vary in different world regions.

Multiple genes have been shown to be independently hypermethylated in lymphoid malignancies. We report here on the extent of concurrent methylation of E-cadherin, Dap-kinase, O 6 MGMT, p73, p16, p15 and p14 in 129 pediatric ALL cases. While most of these genes demonstrated methylation in a proportion of cases, O 6 MGMT, p16 and p14 were infrequently methylated (11, 7 and 3%, respectively). Methylation of at least one gene was found in the vast majority (83%) of cases. To determine the extent and concordance of methylation we calculated a methylation index (MI ¼ number of methylated genes/number of studied genes) for each sample. The average MI was 0.28, corresponding to 2/7 methylated genes. MI was correlated with standard prognostic factors, including immunophenotype, age, sex, WBC and presence of specific translocations (TEL-AML1, BCR-ABL, E2A-PBX1 or MLL-AF4). We determined that children X10 years old and children presenting with high WBC (X50 Â 10 9 /l) both associated with a higher MI (Po0.01 and o0.05, respectively). T-ALLs demonstrated a lower MI (median ¼ 0.17) than precursor B ALLs (median ¼ 0.28). Among the different molecular subgroups, MLL-ALLs had the highest MI (mean ¼ 0.35), while ALLs carrying the t(1;19) had the lowest MI (mean ¼ 0.07). The most common epigenetic lesion in childhood ALL was methylation of E-cadherin (72%) independent of the molecular subtype or other clinicopathological factors.

This study examined the salient clinical and epidemiological characteristics of retinoblastoma (RB) in India, thereby highlighting the problems encountered there. The epidemiological characteristics of 296 patients with RB over 8 years were evaluated using hospital records and postal follow-ups. Unilateral disease was seen in 61.8% of patients. The overall median age at presentation was 3.5 years (3.5 years for unilateral RB and 1.0 years for bilateral RB). The male/female ratio was 1.4:1. The median duration of symptomatic disease was 8 months. Consanguineous marriage was seen in 17% and family history of RB was noted in 1.7% cases. Also, 2% had a history of other malignancy in the family. Associated congenital malformation was seen in 10.5% of cases. A second malignancy was seen in 0.67% of cases at a mean duration of 4.5 years after completion of therapy. A predominance of advanced-stage disease (74.5% had Reese-Ellsworth group IV and V disease) was seen in our series. Only 43.6% of patients had disease localized to the globe without any infiltration/invasion. The majority of cases had advanced-stage disease at presentation and came from the underprivileged class of society. Patients with bilateral RB presented much earlier than those with unilateral disease. In patients with unilateral RB, higher age at presentation as well as advanced disease may be related to much delay in seeking medical attention. In view of the advanced stage at presentation, there also exist a possibility of difference in the biology of the tumor seen in these patients.