Physical and Functional Association of the Major Histocompatibility Complex Class I Heavy Chain �3 Domain with the Transporter Associated with Antigen Processing

CD8 � T lymphocytes recognize antigens as short, MHC class I-associated peptides derived by processing of cytoplasmic proteins. The transporter associated with antigen processing translocates peptides from the cytosol into the ER lumen, where they bind to the nascent class I molecules. To date, the precise location of the class I-TAP interaction site remains unclear. We provide evidence that this site is contained within the heavy chain �3 domain. Substitution of a 15 amino acid portion of the H-2D b �3 domain (aa 219-233) with the analogous MHC class II (H-2IA d) �2 domain region (aa 133-147) results in loss of surface expression which can be partially restored upon incubation at 26�C in the presence of excess peptide and �2-microglobulin. Mutant H-2D b (D b 219-233) associates poorly with the TAP complex, and cannot present endogenously-derived antigenic peptides requiring TAP-dependent translocation to the ER. However, this presentation defect can be overcome through use of an ER targeting sequence which bypasses TAP-dependent peptide translocation. Thus, the �3 domain serves as an important site of interaction (directly or indirectly) with the TAP complex and is necessary for TAP-dependent peptide loading and class I surface expression. The MHC class I molecule is a heterotrimeric comple

Immunohistochemical screening for anaplastic lymphoma kinase (ALK) rearrangement in advanced non-small cell lung cancer patients

Fluorescence in situ hybridization (FISH) is currently used to detect non-small cell lung cancer (NSCLC) patients with anaplastic lymphoma kinase (ALK) gene rearrangement, who are candidates for ALK inhibitor therapy. However. FISH may not be a practical method for screening for ALK-positive patients in a large population due to its cost and difficulty in interpretation. We investigated the role of immunohistochemistry (IHC) to screen for ALK rearrangement in advanced NSCLC. We identified 1,166 stage IIIB or IV NSCLC patients with non-squamous histology from the Seoul National University Hospital NSCLC database. To enrich ALK-positive cases, we selected 262 patients who were either EGFR wild-type or non-responders to previous EGFR tyrosine kinase inhibitors (TKI). ALK IHC and ALK FISH were performed on formalin-fixed, paraffin-embedded tissue. ALK protein was expressed in 28 (10.7%) tumors in 262 patients. ALK FISH was positive in 25 (9.5%) cases. All patients with IHC score of 3 (n = 9) were FISH-positive and all patients with score of 0 (n = 234) were FISH-negative. Among patients with IHC scores of 1 and 2, five (83.3%, 5/6) and eleven (84.6%, 11/13) were FISH-positive, respectively. The sensitivity and specificity of ALK IHC with intensity score of 1 or more were 100% and 98.7%, respectively. IHC can be a useful test for screening ALK FISH-positive cases in advanced NSCLC. FISH testing should be considered for advanced NSCLC patients with tumors showing mild to moderate staining for ALK by IHC to confirm ALK translocation. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

Comparative analyses of overall survival in patients with anaplastic lymphoma kinase-positive and matched wild-type advanced nonsmall cell lung cancer

BACKGROUND: The purpose of this study was to investigate the overall survival (OS) of patients with advanced ALK-positive nonsmall cell lung cancer (NSCLC) who were managed in the pre-ALK inhibitor era and to compare their survival with that of a matched case cohort of ALK wild-type (WT) patients. METHODS: Data from 1166 patients who had stage IIIB/IV NSCLC with nonsquamous histology were collected from the NSCLC database of Seoul National University Hospital between 2003 and 2009. ALK fluorescence in situ hybridization (FISH) was used to analyze 262 patients who either had the WT epidermal growth factor receptor (EGFR) or were nonresponders to previous EGFR tyrosine kinase inhibitor (TKI) therapy. Overall survival (OS) was compared between 3 groups: 1) ALK-positive patients, 2) EGFR mutation-positive patients, and 3) ALK-WT/EGFR-WT patients. Progression-free survival (PFS) after first-line chemotherapy and EGFR TKIs also was analyzed. RESULTS: Twenty-three patients were ALK-positive according to FISH analysis and did not receive ALK inhibitors during follow-up. The median OS for ALK-positive patients, EGFR mutation-positive patients, and WT/WT patients was 12.2 months, 29.6 months, and 19.3 months, respectively (vs EGFR mutation-positive patients, P = .001; vs WT/WT, P = .127). The PFS after first-line chemotherapy for the 3 groups was not different. However, the PFS for patients who received EGFR TKIs was shorter in ALK-positive patients compared with the other 2 groups (vs EGFR mutation-positive patients, P < .001; vs WT/WT, P < .021). CONCLUSIONS: In the pre-ALK inhibitor era, ALK-positive patients experienced the shortest survival, although it did not differ statistically from that of WT/WT patients. Although their responses to platinum-based chemotherapy were not different from comparator groups, ALK-positive patients were even more resistant to EGFR TKI treatment than WT/WT patients. Cancer 2012;35793586. (C) 2011 American Cancer Society.

Worse Disease-Free Survival in Never-Smokers with ALK+ Lung Adenocarcinoma

IntroductionThe EML4–anaplastic lymphoma kinase (ALK) translocation is a recognized oncogenic driver in non-small cell lung cancer. We investigated immunohistochemistry (IHC) screening with fluorescence in situ hybridization (FISH) confirmation for ALK detection and estimated the prevalence of ALK positivity in our patient cohort of never-smokers, together with differences in clinical outcomes and prognostic factors for patients with ALK-positive and ALK-negative tumors.MethodsWe designed a three-phase study (training, validation, and testing) in 300 never-smokers with lung adenocarcinoma from the observational Mayo Clinic Lung Cancer Cohort. Tumor samples were tested using IHC and FISH, and concordance between the methods was assessed. Clinical outcomes were assessed via 5-year progression- or recurrence-free survival from diagnosis. Prognostic factors for ALK-positive tumors and metastases were also investigated.ResultsALK-positive patients were significantly (p < 0.05) younger and had higher grade tumors than ALK-negative patients. ALK positivity was 12.2% by IHC and confirmed at 8.2% of tumors by FISH, with complete concordance between IHC 3+/0 and FISH+/− assessments, respectively. Five-year risk of progression or recurrence was doubled for patients with ALK-positive compared with ALK-negative tumors; ALK-positive tumors also appeared to be associated with a higher risk of brain and liver metastases.ConclusionsOur findings suggest that ALK positivity is associated with a significantly poor outcome in nonsmoking-related adenocarcinoma and that ALK-positive tumors may be associated with an increased risk of brain and liver metastases compared with ALK-negative disease. Consequently, an unmet medical need exists in ALK-positive lung cancer patients, and effective ALK-specific therapies are needed

Effect of crizotinib on overall survival in patients with advanced non-small-cell lung cancer harbouring ALK gene rearrangement: a retrospective analysis

BACKGROUND: ALK gene rearrangement defines a new molecular subtype of non-small-cell lung cancer (NSCLC). In a recent phase 1 clinical trial, the ALK tyrosine-kinase inhibitor (TKI) crizotinib showed marked antitumour activity in patients with advanced, ALK-positive NSCLC. To assess whether crizotinib affects overall survival in these patients, we did a retrospective study comparing survival outcomes in crizotinib-treated patients in the trial and crizotinib-naive controls screened during the same time period. METHODS: We examined overall survival in patients with advanced, ALK-positive NSCLC who enrolled in the phase 1 clinical trial of crizotinib, focusing on the cohort of 82 patients who had enrolled through Feb 10, 2010. For comparators, we identified 36 ALK-positive patients from trial sites who were not given crizotinib (ALK-positive controls), 67 patients without ALK rearrangement but positive for EGFR mutation, and 253 wild-type patients lacking either ALK rearrangement or EGFR mutation. To assess differences in overall survival, we assessed subsets of clinically comparable ALK-positive and ALK-negative patients. FINDINGS: Among 82 ALK-positive patients who were given crizotinib, median overall survival from initiation of crizotinib has not been reached (95% CI 17 months to not reached); 1-year overall survival was 74% (95% CI 63-82), and 2-year overall survival was 54% (40-66). Overall survival did not differ based on age, sex, smoking history, or ethnic origin. Survival in 30 ALK-positive patients who were given crizotinib in the second-line or third-line setting was significantly longer than in 23 ALK-positive controls given any second-line therapy (median overall survival not reached [95% CI 14 months to not reached] vs 6 months [4-17], 1-year overall survival 70% [95% CI 50-83] vs 44% [23-64], and 2-year overall survival 55% [33-72] vs 12% [2-30]; hazard ratio 0·36, 95% CI 0·17-0·75; p=0·004). Survival in 56 crizotinib-treated, ALK-positive patients was similar to that in 63 ALK-negative, EGFR-positive patients given EGFR TKI therapy (median overall survival not reached [95% CI 17 months to not reached] vs 24 months [15-34], 1-year overall survival 71% [95% CI 58-81] vs 74% [61-83], and 2-year overall survival 57% [40-71] vs 52% [38-65]; p=0·786), whereas survival in 36 crizotinib-naive, ALK-positive controls was similar to that in 253 wild-type controls (median overall survival 20 months [95% CI 13-26] vs 15 months [13-17]; p=0·244). INTERPRETATION: In patients with advanced, ALK-positive NSCLC, crizotinib therapy is associated with improved survival compared with that of crizotinib-naive controls. ALK rearrangement is not a favourable prognostic factor in advanced NSCLC. FUNDING: Pfizer Inc, V Foundation for Cancer Research. TRIAL REGISTRATION: ClinicalTrials.gov NCT00585195