The isotype of the BCR as a surrogate for the GCB and ABC molecular subtypes in diffuse large B-cell lymphoma

Gene expression profiling has identified two major molecular subtypes of diffuse large B-cell lymphoma (DLBCL) that are histologically indistinguishable but differ in cure rates. Here, we investigated whether the isotype of the B-cell receptor (BCR) expressed by the tumoral cells correlated with the molecular subtype and survival. Gene expression analysis clustered the 53 patients included in this study into three subgroups, 17 germinal center B-cell-like (GCB) cases, 26 activated B-cell-like (ABC) cases and 10 intermediate cases. The molecular subtype was correlated with the isotype, as 15/17 GCB cases expressed a secondary isotype (immunoglobulin (Ig)G or IgA), whereas 24/26 ABC cases expressed a primary isotype (IgM or IgD) (P<0.0001). There was a trend toward a worse outcome for patients with an ABC DLBCL and a shorter overall survival for patients with IgM+ tumor (P=0.21 and 0.014, respectively). Finally, fluorescence in situ hybridization (FISH) analysis revealed a striking asymmetric pattern, as the IGHM gene is conserved only on the productive IGH allele in most IgM+ tumors. Taken together, these data indicate that the isotype of the BCR is a reliable indicator for the GCB and ABC subtypes in DLBCL, and suggest that the conservation of an IgM is required for ABC DLBCL lymphomagenesis to occur.

Occupational changes in manual tactile sensibility of the dentist

The aim of this study was to find out if the use of vibrating tools (drill, ultrasonic scaler ...) in dental practice has negative side effects on the manual tactile sensibility of the dentist. The sensory tests were performed on 50 subjects, who were allocated to three different groups according to their occupation and the length of their working experience. The first test group consisted of 20 dentists, who had more than 25 years of work experience. As a control group, 20 non-dentists were recruited to obtain a similar age distribution as the former test group. A final group consisted of 10 dentists with more than 1 year of work experience. All subjects underwent three tests: light-touch sensation test, two-point discrimination test and thermal sensation test on the thumb and the index finger of the working and non-working hands. Results showed significant differences, especially for the light-touch sensation test. The study showed more specifically that the tactile sensibility of the working hand of the dentists with more than 25 years of work experience was significantly diminished with respect to the non-working hand and to the working hand of non-dentists. In the test group of young dentists, there was no noticeable reduction of manual tactile sensibility.

MSH2 and adjuvant cisplatin-based chemotherapy in non-small cell lung cancer

CRA7502

Background: Adjuvant cisplatin-based chemotherapy improves survival among patients with non-small cell lung cancer. The human MutS homolog 2 (MSH2) protein is required to repair cisplatin-DNA lesions. Methods: We used immunohistochemistry to determine MSH2 expression in specimens from patients who had been enrolled in the International Adjuvant Lung Trial. The long-term (median follow-up 7.5 years) overall survival benefit was evaluated in a Cox model adjusted on clinical and pathological variables. Results: Among 673 evaluable tumors, 257 (38%) were MSH2 positive and 416 (62%) were MSH2 negative. The long-term survival benefit of chemotherapy was likely different according to MSH2 expression (test for interaction, P=0.06): chemotherapy compared with observation prolonged survival in the MSH2 negative group (adjusted hazard ratio for death, 0.76; 95%CI, 0.59 to 0.97; P=0.03), but not in the MSH2 positive group (adjusted hazard ratio for death, 1.12; 95%CI, 0.81 to 1.55; P=0.48). In the control arm, the adjusted hazard ratio for death associated with MSH2 positivity compared to MSH2 negativity was 0.66 (95%CI, 0.49 to 0.90; P=0.01). Among 658 patients with available excision repair cross-complementing group 1 (ERCC1) data, the benefit of chemotherapy decreased with the number of positive markers among MSH2 and ERCC1 (P=0.01). Chemotherapy compared with observation prolonged survival in the combined MSH2 negative/ERCC1 negative subgroup (adjusted hazard ratio for death, 0.65; 95%CI, 0.47 to 0.91; P=0.01). Conclusions: MSH2 appears to predict a long-term benefit from adjuvant cisplatin-based chemotherapy in patients with non-small cell lung cancer and may be combined with ERCC1.

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MSH2 and adjuvant cisplatin-based chemotherapy in non-small cell lung cancer

CRA7502

The full, final text of this abstract will be available in Part II of the 2009 ASCO Annual Meeting Proceedings, distributed onsite at the Meeting on May 30, 2009, and as a supplement to the June 20, 2009, issue of the Journal of Clinical Oncology.

[Table: see text]