Multifocal Lung Adenocarcinomas Research Articles

How Should Synchronous Multiple Primary Adenocarcinomas of the Lung Be Resected?

We often encounter patients with multiple primary lung cancers with ground-glass opacity. However, there are no established guidelines regarding the optimal extent of resection for multifocal lung adenocarcinoma, so it is necessary to determine the most suitable strategy for each case. A 62-year-old man visited our hospital with 7 lesions in the lung field. We evaluated the structural information using high-resolution computed tomography (HRCT) and the aggressiveness of the tumors using fluorodeoxyglucose-positron emission tomography/CT (FDG-PET/CT) and then developed a surgical strategy. Using FDG-PET/CT in addition to HRCT might improve the selection of appropriate surgical strategies for patients with multifocal lung adenocarcinoma.

Abstract LB-360: Afatinib prolonged survival in EGFR-driven lung cancer model compared to gefitinib

Abstract Afatinib (BIBW2992) is an irreversible pan-HER inhibitor. Kinase inhibitors have different dissociation constant for binding deletion mutation and point mutation in EGFR. We previously reported that afatinib with short-term (4 weeks) administration tended to be more effective for treatment of lung cancer model induced by the deletion mutation in exon 19 than gefitinib, although similar effect of both drugs was observed in L858R mutated mice (#3566, AACR 2011). Our present study was carried out to investigate the preclinical efficacy of long-term treatment of afatinib in lung cancer harboring deletion mutation in EGFR exon 19. We generated transgenic mice expressing the delE748-A752 mutant of mouse EGFR, which is equivalent to the delE746-A750 mutant, driven by the SP-C promoter (Cancer Sci 99, 2008). The mice invariably developed multi-focal lung adenocarcinomas of various sizes at 5 weeks of age and died of lung cancer, if left untreated. To evaluate the efficacy of afatinib on survival in the mice, afatinib, gefitinib (5 mg/kg/day, n=15 each) or vehicle alone (n=13) was administered orally from 7 weeks of age until inability to take due to toxicity or death. All mice in the control group died and the median survival time (MST) was 17 weeks. At the time, 12 gefitinib-treated mice and 6 afatinib-treated mice died, and the afatinib-treated mice survived longer significantly than gefitinib-treated mice (MST: not reached vs 54 weeks; p < 0.05 by logrank test). No toxic death was observed in all mice. After the initiation of treatment at week 4, the body weight of the mice in the control group was significantly lower than that in gefitinib or afatinib group. The gefitinib-treated mice significantly lost weight compared to afatinib-treated mice after 34 weeks. To understand the efficacy of afatinib in the mice, EGFR/HER2 protein expression was determined by immunoblotting assay. The mice of 14 weeks of age were sacrificed at 2, 6, 10, 14, and 18 hours after single administration of each drug. In gefitinib-treated mice, phosphorylated EGFR (pEGFR) was suppressed at 2 and 6 hours but was recovered at 10 hours. On the other hand, in afatinib-treated mice, pEGFR was suppressed at 2, 6, and 10 hours and was partially recovered at 14 and 18 hours. At 14 hours, the expressions of pEGFR in gefitinib-treated mice and in afatinib-treated mice were more and less than those in mice without treatment, respectively. In gefitinib-treated mice, phosphorylated HER2 (pHER2) was recovered at 10 hours after decreasing at 2 and 6 hours. Presumably, EGFR/HER2 heterodimer might be suppressed temporally by gefitinib. In afatinib-treated mice, pHER2 was suppressed from 2 to 18 hours. The results suggest that afatinib is more effective than gefitinib because it suppresses pEGFR for longer time than gefitinib. In conclusion, our data suggest that afatinib can well control lung cancer driven by EGFR exon19 deletion mutation longer than gefitinib. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-360. doi:1538-7445.AM2012-LB-360

Lung tumour growth kinetics in SPC-c-Raf-1-BB transgenic mice assessed by longitudinal in-vivo micro-CT quantification

BackgroundSPC-c-Raf-1-BxB transgenic mice develop genetically induced disseminated lung adenocarcinoma allowing examination of carcinogenesis and evaluation of novel treatment strategies. We report on assessment of lung tumour growth kinetics using a semiautomated region growing segmentation algorithm.Methods156 non contrast-enhanced respiratory gated micro-CT of the lungs were obtained in 12 SPC-raf transgenic (n = 9) and normal (n = 3) mice at different time points. Region-growing segmentation of the aerated lung areas was obtained as an inverse surrogate for tumour burden. Time course of segmentation volumes was assessed to demonstrate the potential of the method for follow-up studies.ResultsMicro-CT allowed assessment of tumour growth kinetics and semiautomated region growing enabled quantitative analysis. Significant changes of the segmented lung volumes over time could be shown (p = 0.009). Significant group differences could be detected between transgenic and normal animals for time points 8 to 13 months (p = 0.043), when marked tumour progression occurred.ConclusionThe presented region-growing segmentation algorithm allows in-vivo quantification of multifocal lung adenocarcinoma in SPC-raf transgenic mice. This enables the assessment of tumour load and progress for the study of carcinogenesis and the evaluation of novel treatment strategies.

Clonality status of multifocal lung adenocarcinomas based on the mutation patterns of EGFR and K-ras

PurposeThe purpose of this study is to clarify the clonality status of multifocal lung adenocarcinomas based on the mutation patterns of epidermal growth factor receptor (EGFR) and K-ras. MethodsWe analyzed 82 multifocal lung adenocarcinomas from 36 patients who underwent surgical resection. Genomic DNA was extracted from formalin-fixed, paraffin-embedded tissue and analyzed for EGFR and K-ras mutations. We determined the clonality status of multifocal lung adenocarcinomas based on the mutation patterns of EGFR and K-ras. The actuarial survival time was estimated and the prognostic factors were evaluated for 31 patients with synchronous multifocal lung adenocarcinomas. ResultsEGFR and K-ras mutations were detected in 36 (44%) and 19 (23%) of the 82 tumors, respectively. EGFR mutations had occurred randomly in 20 (91%) of the 22 patients with at least one EGFR mutated tumor. K-ras mutations had occurred randomly in 14 (93%) of the 15 patients with at least one K-ras mutated tumor. Combining the results for the EGFR and K-ras mutation patterns, the clonality status of multifocal lung adenocarcinomas could be determined in 30 (83%) of the 36 patients. No statistically significant difference in the actuarial survival of the patient subgroups stratified according to the clonality status, which was based on the presence of EGFR and K-ras mutations, was observed. ConclusionsBoth EGFR and K-ras mutations frequently occur randomly in multifocal lung adenocarcinomas. Combined mutation pattern analyses of EGFR and K-ras may be useful for making decisions regarding treatment strategies for patients with multifocal lung adenocarcinomas.

Combined mutation pattern analyses of epidermal growth factor receptor and K-ras genes for the differential diagnosis of primary versus metastatic lung adenocarcinomas.

e21010 Background: The differential diagnosis of multiple primary lung cancers (MPLCs) from pulmonary metastases (PMs) is sometimes difficult based solely on the Martini and Melamed's criteria. We investigated whether combined mutation pattern analyses of the epidermal growth factor receptor (EGFR) and K-ras genes were useful for differentiating between MPLCs and PMs. Methods: We conducted a retrospective review of 84 tumors (81 adenocarcinomas and three atypical adenomatous hyperplasias) in 36 patients with multifocal lung adenocarcinomas. Genomic DNA was extracted from paraffin-embedded tissue. The peptide nucleic acid (PNA)-locked nucleic acid polymerase chain reaction clamp method was used for EGFR mutation analysis. The PNA-mediated PCR clamping method was used for K-ras mutation analysis. We determined clonality status of secondary tumors based on the mutation patterns of EGFR and K-ras by comparing them with primary tumors. Correlations between the mutation status and the proportion of bronchioloalveolar carcinoma (BAC) component in a tumor were examined. Results: EGFR and K-ras mutations were detected in 38 (45%) and 24 (29%) of 84 tumors, respectively. Thirty-four (71%) of secondary tumors were diagnosed as a different clonality (MPLC). Seven (15%) of secondary tumors were classified into the same clonality (PM). Clonality status could not be determined for the seven (15%) remaining secondary tumors. A clonality assessment based on the EGFR and K-ras mutation status was possible in 41 (84%) of 48 secondary tumors, and it was consistent with the Martini and Melamed's criteria in 29 (71%) of 41 secondary tumors. The proportion of BAC component in a tumor did not correlate with the EGFR/K-ras mutation status. Conclusions: The combined mutation pattern analyses of EGFR and K-ras enabled a definite distinction between PMLCs and PMs in a large portion of multifocal lung adenocarcinomas. Mutations of EGFR and K-ras in multifocal lung adenocarcinomas frequently occurred randomly, which support the concept of “field cancerization.” No significant financial relationships to disclose.

Induction of lung adenocarcinoma in transgenic mice expressing activated EGFR driven by the SP‐C promoter

To investigate the role of an activating epidermal growth factor receptor (EGFR) mutation in lung cancer, we generated transgenic mice expressing the delE748-A752 mutant version of mouse EGFR driven by the SP-C promoter, which is equivalent to the delE746-A750 mutation found in lung cancer patients. Strikingly, the mice invariably developed multifocal lung adenocarcinomas of varying sizes at between 5 and 6 weeks of age, and they died from tumor progression approximately 2 months later if left untreated. Daily oral administration of the EGFR tyrosine kinase inhibitor (TKI) gefitinib (5 mg/kg/day) reduced the total and phosphorylation levels of EGFR to those in wild-type mouse lung tissue; in addition, it abrogated tumor growth within 1 week and prolonged survival to >30 weeks. Interestingly, phosphorylated ErbB2, ErbB3, and thyroid transcriptional factor-1 increased in the transgenic mice compared with those in wild-type mice. They might play some roles in tumors progression in the transgenic mice. This model will be useful for studying the mechanisms of carcinogenesis, chemoprevention, and acquired resistance to EGFR TKIs in lung cancer patients carrying activating EGFR mutations.

A selective small molecule inhibitor of c-Met, PHA-665752, reverses lung premalignancy induced by mutant K-ras.

The c-Met receptor tyrosine kinase has been implicated in cellular transformation induced by mutant Ras, a commonly activated proto-oncogene in non-small cell lung cancer (NSCLC). However, the role of c-Met has not been defined in K-ras-mutant NSCLC, a disease for which no effective targeted therapeutic options currently exist. To acquire a greater understanding of its role, we used genetic and pharmacologic approaches to inhibit c-Met in mice and cultured cells. In Kras(LA1) mice, which develop premalignant lung lesions that progress to multifocal lung adenocarcinomas owing to somatic mutations in K-ras, c-Met was expressed in multiple cell types within premalignant lung lesions, and high concentrations of HGF were detected in bronchoalveolar lavage samples. Short-term treatment with PHA-665752, a c-Met inhibitor, decreased the numbers of premalignant lung lesions and induced apoptosis in tumor cells and vascular endothelial cells within lesions. In cell culture, PHA-665752 induced apoptosis of a lung adenocarcinoma cell line derived from Kras(LA1) mice (LKR-13) and a murine lung endothelial cell line (MEC). c-Met depletion by siRNA transfection induced apoptosis of MECs but not LKR-13 cells. Collectively, these findings suggest that apoptosis was an on-target effect of PHA-665752 in MECs but not in LKR-13 cells. We conclude that PHA-665752 inhibited lung tumorigenesis in Kras(LA1) mice and may provide a novel therapeutic approach to the prevention of K-ras-mutant NSCLC.