Person:

Chirieac, Lucian

In a subset of lung adenocarcinomas the epidermal growth factor receptor (EGFR) is activated by kinase domain mutations and/or gene amplification, but the interaction between the two types of abnormalities is complex and unclear. We selected to study 99 consecutive never-smoking women of East Asian origin with lung adenocarcinomas that were characterized by histologic subtype. We analyzed EGFR mutations by PCR-capillary sequencing, EGFR copy number abnormalities by fluorescence and chromogenic in situ hybridization and quantitative PCR, and EGFR expression by immunohistochemistry with both specific antibodies against exon 19 deletion-mutated EGFR and total EGFR. We compared molecular and clinicopathologic features with disease-free survival. Lung adenocarcinomas with EGFR amplification had significantly more EGFR exon 19 deletion mutations than adenocarcinomas with disomy, low and high polysomy (100% v 54%, P=0.009). EGFR amplification occurred invariably on the mutated and not the wildtype allele (median mutated:wildtype ratios 14.0 v .33, P=0.003), was associated with solid histology (P=0.008), and advanced clinical stage (P=0.009). EGFR amplification was focally distributed in lung cancer specimens, mostly in regions with solid histology. Patients with EGFR amplification had a significantly worse outcome in univariate analysis (median disease-free survival 16 v 31 months, P=0.01) and when adjusted for stage (P=0.027). Lung adenocarcinomas with EGFR amplification have a unique association with exon 19 deletion mutations and demonstrate distinct clinicopathologic features associated with a significantly worsened prognosis. In these cases, EGFR amplification is heterogeneously distributed, mostly in areas with a solid histology.

Many patients with stage I non-small cell lung carcinoma will develop recurrence following surgical excision. Sox2 is a marker of embryonic stem cell pluripotency that is associated with aggressive tumor behavior and is expressed in a subset of lung adenocarcinomas. We hypothesized that Sox2 expression may provide prognostic information in early stage lung adenocarcinomas. We evaluated formalin-fixed paraffin embedded tissue from 104 stage I lung adenocarcinomas resected between 1997 and 2000. Sox2 expression was analyzed by immunohistochemistry and compared to clinicopathologic features, time-to-progression (TTP) and overall survival (OS). Sox2 expression was detected in 50% of cases and was more frequent in tumors from older and male patients but not significantly associated with smoking status, tumor stage, grade, or histologic subtype. Compared to Sox2-negative tumors, Sox2 expression predicted a shorter TTP (49% versus 82% at 5 years; P = 0.0006) and shorter OS (54% versus 79% at 5 years; P = 0.004). By multivariate analysis, Sox2 expression predicted a greater risk of progression among men (hazard ratio [HR] 5.6; 95% CI 2.3 to 13.8) and women (HR 2.1; 95% CI 0.8 to 5.7). Sox2 expression was associated with significantly shorter OS among men (HR 2.5; 95% CI 1.2 to 5.1), but not in women. Sox2 appears to be an independent predictor of poor outcome in stage I lung adenocarcinomas and may help stratify patients at increased risk for recurrence.

Background Although grading has prognostic significance for many tumor types, a prognostically significant grading system for lung adenocarcinoma has not yet been established. The aim of this study was to evaluate histologic characteristics included in tumor grading systems, establish optimal cutoff values that have the strongest association with overall survival, and develop a grading system incorporating the histopathologic characteristics that we found to have prognostic significance in patients with lung adenocarcinoma.

Methods We studied lung adenocarcinomas from 85 consecutive patients, and evaluated the percentage of solid pattern (as a reflection of tumor architecture), the degree of cytologic atypia, and the mitotic count.

Results In univariate analysis, overall survival was associated significantly with sex (P=0.045), age (P=0.0008), tumor status (P<0.0001), node status (P=0.02), solid pattern (P=0.046) and cytologic atypia (P=0.01), but not with mitotic count (P=0.26). Based on optimal cutoff values, we found that a solid pattern ≥ 90% and severe cytologic atypia were the best discriminators of worse outcome. A grading score, computed as the sum of the architecture score and cytologic atypia score (2=well differentiated, 3=moderately differentiated, 4=poorly differentiated), was a significant predictor of overall survival in univariate analysis (median overall survival times 72.4, 39.5, and 8.7 months for well, moderately and poorly differentiated adenocarcinoma, respectively P=0.0001). Moreover, grading was an independent predictor of survival in multivariate analysis (P=0.002).

Conclusions We describe a grading system that incorporates the percentage of solid pattern and degree of the cytologic atypia that is an independent predictor of survival in patients with lung adenocarcinoma.

BACKGROUND There are no reliable markers able to identify patients with non-small cell lung cancer (NSCLC) likely to metastasize to the brain. We investigated associations between immunohistochemical markers and development of brain metastases in patients with NSCLC.

METHODS We performed a hospital-based, case-control study of patients with newly diagnosed NSCLC between 1989 and 2003 that developed brain metastases who had available pathology material from both primary NSCLC and brain metastases. The control patients had NSCLC and no evidence of brain metastases. We examined NSCLC for expression of Ki-67, caspase-3, VEGF-A, VEGF-C, E-cadherin and EGFR in 54 surgical pathology specimens using immunohistochemistry and evaluated associations with development of brain metastases.

RESULTS Brain metastases developed after a median time of 12.5 months (range 1.7-89.4 months) from the diagnosis of NSCLC. A significantly increased risk of developing brain metastases was associated with patients who had high Ki-67 (adjusted odds ratio 12.2, 95% CI, 2.4 to 70.4, P<0.001), low caspase-3 (adjusted odds ratio 43.0, 95% CI, 5.3 to >100, P<0.001), high VEGF-C (adjusted odds ratio 14.6, 95% CI, 2.0 to >100, P<0.001), and low E-cadherin (adjusted odds ratio 3.6, 95% CI, 0.9 to 16.4, P=0.05), in the primary NSCLC. No significant risk was observed with VEGF-A and EGFR. A high Ki-67 was also associated with a shorter overall survival (P=0.04).

CONCLUSIONS Patients with NSCLC and high Ki-67, low caspase-3, high VEGF-C, and low E-cadherin in their tumors may benefit from close surveillance since they may have an increased risk of developing brain metastases.

Malignant pleural mesothelioma (MPM) is an aggressive cancer that occurs more frequently in men, but is associated with longer survival in women. Insight into the survival advantage of female patients may advance the molecular understanding of MPM and identify therapeutic interventions that will improve the prognosis for all MPM patients. In this study, we performed whole-genome sequencing of tumor specimens from 10 MPM patients and matched control samples to identify potential driver mutations underlying MPM. We identified molecular differences associated with gender and histology. Specifically, single-nucleotide variants of BAP1 were observed in 21% of cases, with lower mutation rates observed in sarcomatoid MPM (p<0.001). Chromosome 22q loss was more frequently associated with the epithelioid than that non-epitheliod histology (p=0.037), whereas CDKN2A deletions occurred more frequently in non-epithelioid subtypes among men (p=0.021) and were correlated with shorter overall survival for the entire cohort (p=0.002) and for men (p=0.012). Furthermore, women were more likely to harbor TP53 mutations (p=0.004). Novel mutations were found in genes associated with the integrin-linked kinase pathway, including MYH9 and RHOA. Moreover, expression levels of BAP1, MYH9, and RHOA were significantly higher in non-epithelioid tumors, and were associated with significant reduction in survival of the entire cohort and across gender subgroups. Collectively, our findings indicate that diverse mechanisms highly related to gender and histology appear to drive MPM.

Purpose To develop a standardized approach for molecular diagnostics, we used the gene-expression ratio bioinformatic technique to design a molecular signature to diagnose MPM from among other potentially confounding diagnoses and differentiate the epithelioid from the sarcomatoid histological subtype of MPM. In addition, we searched for pathways relevant in MPM in comparison to other related cancers to identify unique molecular features in MPM.

Experimental Design We performed microarray analysis on 113 specimens including MPMs and a spectrum of tumors and benign tissues comprising the differential diagnosis of MPM. We generated a sequential combination of binary gene-expression ratio tests able to discriminate MPM from other thoracic malignancies. We compared this method to other bioinformatic tools and validated this signature in an independent set of 170 samples. Functional enrichment analysis was performed to identify differentially expressed probes.

Results A sequential combination of gene-expression ratio tests was the best molecular approach to distinguish MPM from all the other samples. Bioinformatic and molecular validations showed that the sequential gene ratio tests were able to identify the MPM samples with high sensitivity and specificity. In addition, the gene-ratio technique was able to differentiate the epithelioid from the sarcomatoid type of MPM. Novel genes and pathways specifically activated in MPM were identified.

Conclusions New clinically relevant molecular tests have been generated using a small number of genes to accurately distinguish MPMs from other thoracic samples supporting our hypothesis that the gene-expression ratio approach could be a useful tool in the differential diagnosis of cancers.

Purpose The anaplastic large cell kinase gene (ALK) is rearranged in approximately 5% of lung adenocarcinomas within the Asian population. We evaluated the incidence and the characteristics of ALK-rearranged lung adenocarcinomas within the Western population and the optimal diagnostic modality to detect ALK rearrangements in routine clinical practice.

Experimental Design We tested 358 lung adenocarcinomas from three institutions for ALK rearrangements by fluorescent in-situ hybridization (FISH) and immunohistochemistry (IHC) with and without tyramide amplification (TA). The clinicopathologic characteristics of tumors with and without ALK rearrangements were compared.

Results We identified 20 lung adenocarcinomas (5.6%) with ALK rearrangements within our cohort of Western patients. ALK rearrangement was associated with younger age (P = 0.0002), never smoking (P < 0.0001), advanced clinical stage (P = 0.0001), and a solid histology with signet-ring cells (P < 0.0001). ALK rearrangement was identified by FISH in 95% of cases, IHC with and without TA in 80% and 40% of cases, respectively, but neither FISH nor IHC alone detected all cases with ALK rearrangement on initial screening. None of the ALK-rearranged tumors harbored coexisting EGFR mutations.

Conclusions Lung adenocarcinomas with ALK rearrangements are uncommon in the Western population and represent a distinct entity of carcinomas with unique characteristics. For suspected cases dual diagnostic testing, with FISH and IHC, should be considered to accurately identify lung adenocarcinomas with ALK rearrangement.