Phase II study of the efficacy of gefitinib in patients with non-small cell lung cancer with the EGFR mutations

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Purpose: Recent studies have indicated that the mutations of epidermal growth factor receptor (EGFR) were associated with sensitivity of non-small cell lung cancer (NSCLC) to gefitinib, an EGFR tyrosine kinase inhibitor. The clinical objective of this study was to prospectively evaluate the efficacy of gefitinib in patients with stageIII/IV NSCLC that had the EGFR mutations. Methods: Genomic DNA was extracted from tumor specimens and EGFR mutations in exon 19 and 21 were analyzed by direct sequencing. Patients with stageIII/IV NSCLC who had the EGFR mutations were treated with gefitinib (250mg) orally. Response, survival data and toxicity were assessed. Results: From Nov. 2004 to Dec 2005, 14 patients with the EGFR mutations received gefitinib (median age: 67 years; 2 males, 12 females; 1 smokers, 13 non-smokers; all adenocarcinomas). Two patients discontinued gefitinib and came off study because of interstitial pneumonitis (grade 3) and acne (grade 3), respectively. Response data are available for 12 patients. Two achieved a complete response (CR), seven exhibited a partial response (PR) and three had stable disease (SD). Response rate and disease control rate were 75% and 100%, respectively. There were no grade 3/4 toxicities in these 12 patients. All patients were alive during median follow-up period of 8 months (range 1–13 months). Conclusions: The EGFR mutations could be an excellent predictor of response to gefitinib in NSCLC.

No significant financial relationships to disclose.

A case of primary peritoneal serous papillary carcinoma initially presented by massive bilateral pleural effusions

Primary peritoneal serous papillary carcinoma (PSPC) is a rare primary peritoneal tumor. Clinically, PSPC usually presents with general abdominal discomfort resulting from variable amounts of ascites. In a state of small amounts of ascites, initial manifestation of massive bilateral pleural effusion is unusual. A 76-year-old female nonsmoker with no asbestos exposure complained of dyspnea during exercise. Chest radiograph showed a massive bilateral pleural effusion. Chest computed tomography (CT) revealed irregular pleural thickening and a small amount of ascites. Abdominopelvic CT revealed nodular thickening of the parietal peritoneum, mesenteric or omental nodules, omental cake, and lymphadenopathy in paraaortic regions. Adenocarcinoma cells were found via cytologic examination in bilateral pleural fluids and ascites. Because the primary site of the adenocarcinoma was not found, a surgical biopsy of the right pleural thickening was performed. The final diagnosis was PSPC. The patient was treated with platinum-based chemotherapy. Physicians should be aware of a possibility of PSPC when the radiographic findings show massive bilateral pleural effusion due to pleural carcinomatosis, with high serum levels of CA125.

Papillary adenocarcinoma of the lung is a more advanced adenocarcinoma than bronchioloalveolar carcinoma that is composed of two distinct histological subtypes

To clarify the clinicopathological nature of papillary adenocarcinoma (PA) of the lung, 20 cases of PA were collected consecutively from resected adenocarcinoma of the lung, studied immunohistochemically and, using molecular techniques, compared with bronchioloalveolar carcinoma (BAC). Clinicopathologically, PA occurred in 7.4% and dominantly in female patients. Morphologically, PA was divided into two subtypes according to the presence of residual alveolar structures, detected by elastica van Gieson stain. One of these subtypes was closely related to the morphology of BAC and might be diagnosed as adenocarcinoma with mixed subtypes. The other PA subtype was composed of tall columnar cells and grew compressively, which was similar to type F adenocarcinoma previously reported by Noguchi et al. Immunohistochemical studies using lung tissue-specific antigens, progression markers and tumor suppressor products found that PA seemed a more advanced adenocarcinoma than BAC, but no differences were observed among PA subtypes. Molecular biological analysis using three microsatellite markers at chromosome 3p revealed more frequent loss of heterozygosity in PA than BAC, with no differences among PA subtypes. These findings suggest that PA is a more advanced adenocarcinoma subtype than BAC. Further investigations are needed to clarify true PA as clinicopathologically and biologically independent from other histological subtypes of adenocarcinoma of the lung.

Association of amino acid substitution polymorphisms in DNA repair genes TP53, POLI, REV1 and LIG4 with lung cancer risk

Single nucleotide polymorphisms (SNPs) were searched for in 36 genes involved in diverse DNA repair pathways, and 50 nonsynonymous (associated with amino acid changes) SNPs identified were assessed for associations with lung cancer risk by a case-control study consisting of 752 adenocarcinoma cases, 250 squamous cell carcinoma cases and 685 controls. An SNP, Arg72Pro, of the TP53 gene encoding a DNA damage response protein showed the strongest association with squamous cell carcinoma risk (OR Pro/Pro vs. Arg/Arg = 2.2), while 2 other SNPs, Phe257Ser of the REV gene encoding a translesion DNA polymerase and Ile658Val of the LIG4 gene encoding a DNA double-strand break repair protein, also showed associations (OR Ser/Ser vs. Phe/Phe = 2.0 and OR Ile/Val vs. Ile/Ile = 0.4, respectively). An SNP, Thr706Ala, in the POLI gene encoding another translesion DNA polymerase was associated with adenocarcinoma and squamous cell carcinoma risk, particularly in individuals of ages < 61 years (OR Ala/Ala + Ala/Thr vs. Thr/Thr = 1.5 and 2.4, respectively). POLI is the human counterpart of PolI, a strong candidate for the Par2 (pulmonary adenoma resistance 2) gene responsible for adenoma/adenocarcinoma susceptibility in mice. The present results suggest that these 4 SNPs function as genetic factors underlying lung cancer susceptibility by modulating activities to maintain the genome integrity of each individual.

Evaluation of a whole-genome amplification method based on adaptor-ligation PCR of randomly sheared genomic DNA

High-throughput genetic studies often require large quantities of DNA for a variety of analyses. Developing and assessing a whole-genome amplification method is thus important, especially with the current desire for large-scale genotyping in previously collected samples for which limited DNA is available. The method we have developed, called PRSG, is based on an adaptor-ligation-mediated PCR of randomly sheared genomic DNA. An unbiased representation was evaluated by performing PCR on 2,607 exons of 367 genes, which are randomly distributed throughout the genome, on PRSG products of hundreds of individuals. An infrequent loss (<1%) of the exon sequence on the PRSG products was found. Out of 307 microsatellites on various chromosomes, 258 (84%) were amplified in both the PRSG product and an original DNA, whereas 49 (16%) microsatellites were lost only in the PRSG product. Array CGH analysis of 287 loci for measuring the relative gene copy number demonstrated that a low bias was detected. Moreover, this method was validated on 100-1,000 laser-captured cells from paraffin-embedded tissues. These data show that PRSG can provide a sufficient amount of genomic sequence for a variety of genetic analyses as well as for long-term storage for future work.

Identification of D19S246 as a novel lung adenocarcinoma susceptibility locus by genome survey with 10-cM resolution microsatellite markers

Adenocarcinoma is now the most common histological subtype of lung cancer;however, genetic factors that affect cancer susceptibility are largely unknown. In this study, we performed a systematic survey of the human genome with an average resolution of 10 cM to identify loci that could help us target novel risk genes for lung adenocarcinoma using linkage disequilibrium. Genotyping of DNA "pools" from 100 lung adenocarcinoma cases and 100 controls, respectively, for 322 microsatellite loci dispersed in the human genome led us to identify 5 loci at which allele distribution was significantly (P < 0.05) or marginally (0.05 </= P < 0.1) different between the cases and controls. One of the 5 loci, D19S246 at chromosome 19q13.3, showed significant differences both in the allele and genotype distributions in the subsequent analysis in which 239 lung adenocarcinoma cases and 63 controls were added to the 100 cases and 100 controls used for the initial screening (P = 0.037 and P = 0.026, respectively), whereas the remaining 4 loci did not. These results suggest that the chromosome 19q13.3 region encompassing D19S246 contains a gene(s) of which the genetic polymorphisms are associated with lung adenocarcinoma risk and are in linkage disequilibrium with the D19S246 locus.

Contribution of the NQO1 and GSTT1 polymorphisms to lung adenocarcinoma susceptibility

Lung adenocarcinoma has replaced squamous cell lung carcinoma as the most frequent histological subtype in lung cancers. However, genetic factors that affect cancer susceptibility are much less understood in adenocarcinoma than in squamous cell carcinoma. In this study, polymorphisms in five genes involved in the metabolism of carcinogens or in the repair of damaged DNA in lung cells, NQO1-Pro187Ser, GSTT1-positive/null, GSTM1-positive/null, CYP1A1-Ile462Val, and OGG1-Ser326Cys, were examined for association with lung adenocarcinoma risk in a case-control study of 198 patients and 152 control subjects. The NQO1 and GSTT1 polymorphisms were associated with lung adenocarcinoma risk with adjusted odds ratio of 2.15 for the NQO1-Pro/Pro genotype versus the Ser/Ser genotype and adjusted odds ratio of 1.61 for the GSTT1-null genotype versus the positive genotype, respectively. Furthermore, individuals with the combined genotype of NQO1-Pro/Pro and GSTT1-null showed greater risk compared with those of NQO1-Ser/Ser and GSTT1-positive. In contrast, significant association was not observed for the GSTM1, CYP1A1, and OGG1 polymorphisms with lung adenocarcinoma risk, although several studies have shown their implication in the risk for squamous cell lung carcinoma. The result indicates that the NQO1-Pro/Pro and GSTT1-null genotypes are risk factors for lung adenocarcinoma development, and that the genetic factors for susceptibility to adenocarcinoma are different from those to squamous cell carcinoma. The enhanced risk of the NQO1-Pro/Pro genotype combined with the GSTT1-null genotype was more evident in smokers than in nonsmokers. Therefore, carcinogens in tobacco smoke, which are activated by NQO1 and detoxified by GSTT1, could have a role in lung adenocarcinoma development.

Localization of a human lung adenocarcinoma susceptibility locus, possibly syntenic to the mouse Pas1 locus, in the vicinity of the D12S1034 locus on chromosome 12p11.2-p12.1

Pulmonary adenoma susceptibility 1 (Pas1) is a major locus affecting inherited predisposition to the development of lung adenocarcinoma in mice, and is mapped to chromosome 6q near the Kras2 gene. However, it is still unclear whether the PAS1 locus on human chromosome 12p11.2-p12.1, the region showing synteny to the mouse Pas1 region, is involved in susceptibility to human lung adenocarcinoma development. Thus, we conducted a case-control study of 100 lung adenocarcinoma cases and 100 controls using 20 highly polymorphic microsatellite markers dispersed in a 13 cM region covering a putative PAS1 locus. The differences in the allele and genotype distributions were observed at several loci, and the difference was at a maximum at the D12S1034 locus (P = 0.034 and P = 0.036, respectively). The differences in the allele and genotype distributions at D12S1034 remained significant in the analysis in which 239 lung adenocarcinoma cases and 63 controls were added to the 100 cases and 100 controls used for the initial screening (P = 0.031 and P = 0.027, respectively). The D12S1034 locus was located 800-1350 kb proximal to the KRAS2 locus, and in the region syntenic to the core Pas1 region of approximately 1.5 Mb in size where a single haplotype is shared by several mouse-inbred strains susceptible to lung adenocarcinoma development. These results indicate that the PAS1 locus is located in the vicinity of D12S1034 and a genetic variation(s) at this locus is involved in susceptibility to human lung adenocarcinoma.