BACKGROUND: KRAS and epidermal growth factor receptor (EGFR) mutations are thought to play an important role in the carcinogenesis of lung adenocarcinoma. However, clinicopathological findings of KRAS mutated adenocarcinoma cases have not yet been fully clarified. The authors analyzed the relationship between the KRAS mutation and corresponding clinicopathological findings, focusing on nonmucinous and mucinous bronchioloalveolar elements. METHODS: EGFR and KRAS mutations were detected in DNA samples extracted from 182 surgically resected tissues of lung adenocarcinomas by the Smart Amplification Process. The relations between gene mutation status and clinicopathological features were analyzed. All adenocarcinoma cases were divided into bronchioloalveolar carcinoma (BAC), adenocarcinoma with bronchioloalveolar features, and adenocarcinoma without BAC components (non‐BAC). BAC/adenocarcinoma with bronchioloalveolar features tumors were further assessed for the presence of mucinous features. RESULTS: EGFR and KRAS mutations were found in 76 and 30 cases, respectively. In the KRAS mutant group, BAC/adenocarcinoma with bronchioloalveolar features was found in 22 cases, which included 10 nonmucinous and 12 mucinous tumors. Of 19 cases with mucinous BAC/adenocarcinoma with bronchioloalveolar features, KRAS mutations were detected in 12, but no EGFR mutation was detected. In the KRAS mutant group, BAC/adenocarcinoma with bronchioloalveolar features had significantly earlier pathological stages and more favorable prognoses than did non‐BAC. Mucinous BAC/adenocarcinoma with bronchioloalveolar features showed less smoking history than did nonmucinous BAC/adenocarcinoma with bronchioloalveolar features and non‐BAC. Furthermore, transversion type KRAS mutations were more common in non‐BAC. CONCLUSIONS: KRAS mutated adenocarcinomas can be divided into BAC/adenocarcinoma with bronchioloalveolar features and non‐BAC types. Non‐BAC adenocarcinoma is related to smoking history and has a poor prognosis. BAC/adenocarcinoma with bronchioloalveolar features adenocarcinoma, however, has a more favorable prognosis, and mucinous BAC/adenocarcinoma with bronchioloalveolar features has little relationship to smoking history. Cancer 2011;. © 2011 American Cancer Society.
Recent evidence indicates that the presence of epidermal growth factor receptor (EGFR) or KRAS mutations in non-small cell lung cancer (NSCLC) can predict the response of the tumor to gefinitib. However, it is difficult to detect these mutations using formalinfixed , paraffin-embedded (FFPE) tissues because the fixation process and aging can damage the DNA. In this study , we describe our work in adapting the Smart Amplification Process version 2 (SmartAmp2) to detect EGFR or KRAS mutations in DNA extracted from FFPE tissues. We were able to detect these mutations in 37 (97%) of 38 FFPE lung cancer tissue samples within 60 minutes with the SmartAmp2 assay and to confirm the correlation between EGFR mutations in FFPE tissues and gefitinib responsiveness. All mutations had previously been confirmed in the 38 samples using DNA extracted from frozen tissues. Electrophoresis results indicated that PCR analysis was not reliable for DNA extracted from FFPE tissue when primers with a long amplicon (>300 bp) were used. This study confirms that the SmartAmp2 assay is suitable for use with DNA extracted from FFPE as well as frozen tissues.
Our study clarified the anatomic variety of the vessels in right-sided colon cancer. Preoperative 3D-CT is useful for understanding the anatomy to ensure a safe, precise operation.
KRAS is an oncogene that can be activated by mutations. Patients with non-small cell lung cancer who have KRAS mutations do not respond to tyrosine kinase inhibitors; therefore , accurate detection of KRAS mutations is important for deciding therapeutic strategies. Although sequencing-related techniques have been frequently used , they are usually too complex , have low sensitivity , and are timeconsuming for routine screening in clinical situations. We evaluated peptide nucleic acid (PNA)-clamp smart amplification process version 2 (SmartAmp2) as a detection method for KRAS codon 12 mutations in patient specimens compared with traditional sequencing and polymerase chain reaction-related methods. Among 172 lung adenocarcinoma samples , direct sequencing , enzyme-enriched sequencing , and PNA-enriched sequencing showed that 16 (9.3%) , 26 (15.7%), and 28 (16.3%) tumors , respectively, contained KRAS mutations in codon 12. Using PNA-clamp SmartAmp2 , we could identify 31 (18.0%) tumors that had KRAS mutations in codon 12 within 60 minutes , three of which were undetected by polymerase chain reaction-related methods. On the other hand , we examined 30 nonmalignant peripheral lung tissue specimens and found no mutations in any of the samples using PNA-clamp SmartAmp2. In this study, we confirmed that PNA-clamp SmartAmp2 has high sensitivity and accuracy and is suitable for the clinical diagnosis of KRAS codon 12 mutations. (J Mol
Abstract. Epidermal growth factor receptor (EGFR) gene mutations have been reported to be clinically significant in non-small cell lung cancer (NSCLC). However, because most previous studies focused only on adenocarcinomas, EGFR mutations in other histotypes are poorly investigated. We evaluated the frequency of EGFR gene mutations in squamous cell carcinoma (SCC) and its clinicopathological features. In total, 89 frozen tumor specimens that had been first diagnosed as SCCs, were examined for EGFR mutations in exons 19 and 21 using direct sequencing, PNA-enriched sequencing and SmartAmp2. Additionally, pathological investigation, including immunostaining for p63 and TTF-1, alcian blue staining and EGFR mutation-specific immunohistochemistry in mutation-positive samples was also performed. The frequency of EGFR mutations was 5.6% (5/89); all mutations were deletions in EGFR exon 19. Immunohistological investigation of these samples revealed that two of five were positive for p63 and TTF-1 staining, and showed production of mucin, as evidenced by alcian blue staining. Consequently, three of the samples were considered to be true SCC at final pathological diagnosis, while the remaining two samples were revised to adenosquamous carcinoma and adenocarcinoma. The final frequency of the EGFR mutations in true SCC was 3.4% (3/87). In conclusion, EGFR mutations were found in a small, but significant, number of SCC tumor samples and thus EGFR mutational analysis was useful in the accurate diagnosis of SCC. Our data demonstrate that EGFR mutational analysis should be performed not only in adenocarcinoma, but also in SCC to allow accurate diagnosis and treatment.
Abstract. The presence of EGFR mutations is correlated with a positive therapeutic response to tyrosine kinase inhibitors; therefore, the accurate detection of EGFR mutations is crucial when deciding appropriate therapeutic strategies. Recently, the rapid and sensitive assay smart amplification process version 2 (SmartAmp2) was developed. However, this method can only detect one type of mutation in EGFR exon 19; therefore, we applied the PNA technology to the SmartAmp2 assay to develop PNA-clamp SmartAmp2 for the detection of many types of deletions in EGFR exon 19, in a single reaction. This new assay was evaluated using 172 clinical samples. Thirty-nine (22.7%) samples were found to have deletions by PNA-clamp SmartAmp2; whereas 30 (17.4%) and 38 (22.1%) tumors were found to have deletions by direct sequencing and PNA-enriched sequencing, respectively. Three cases, in which we detected mutations with PNA-clamp SmartAmp2, but not with direct sequencing, were treated with gefitinib, and all cases showed a partial therapeutic response. Using clinical samples, we demonstrated that PNA-clamp SmartAmp2 can detect various types of mutations in EGFR exon 19 in a relatively short time and with high sensitivity. This method detected small amounts of mutant DNA and identified patients for whom clinical information was previously unavailable from other tests. This test may contribute to the administration of efficient therapeutic strategies.
Abstract. We examined the correlation between computed tomography (ct) findings and the incidence of epidermal growth factor receptor (EGFR) and KRas mutations in lung adenocarcinoma. We analyzed the tumors of 136 patients with surgically resected primary lung adenocarcinoma. ct scans were evaluated for the presence of ground grass opacity (ggo), spiculation and the maximum diameter of the tumor was measured. SMart Amplification Process (ver. 2) was used to detect the presence of EGFR and KRas mutations. EGFR and KRas mutations were found in 56 (41.1%) and 25 (18.4%) of the 136 cases, respectively. Although no significant association was found between ggo and EGFR mutations (p=0.07), the EGFR mutation occurred more frequently in male patients with ggo than in those without ggo (p=0.04). the KRas mutation occurred more frequently in patients whose tumor diameter was ≥31 mm than in those whose tumor diameter was <30 mm (p=0.003). Evaluation of CT findings may be helpful for determining the presence of EGFR and KRas mutations, particularly when it is not possible to obtain a tumor specimen.
BackgroundGenetic polymorphisms in the human MDM2 gene are suggested to be a tumor susceptibility marker and a prognostic factor for cancer. It has been reported that a single nucleotide polymorphism (SNP) c.309T>G in the MDM2 gene attenuates the tumor suppressor activity of p53 and accelerates tumor formation in humans.MethodologyIn this study, to detect the SNP c.309T>G in the MDM2 gene, we have developed a new SNP detection method, named “Duplex SmartAmp,” which enabled us to simultaneously detect both 309T and 309G alleles in one tube. To develop this new method, we introduced new primers i.e., nBP and oBPs, as well as two different fluorescent dyes that separately detect those genetic polymorphisms.Results and ConclusionsBy the Duplex SmartAmp method, the genetic polymorphisms of the MDM2 gene were detected directly from a small amount of genomic DNA or blood samples. We used 96 genomic DNA and 24 blood samples to validate the Duplex SmartAmp by comparison with results of the conventional PCR-RFLP method; consequently, the Duplex SmartAmp results agreed totally with those of the PCR-RFLP method. Thus, the new SNP detection method is considered useful for detecting the SNP c.309T>G in the MDM2 gene so as to judge cancer susceptibility against some cellular stress in the clinical setting, and also to handle a large number of samples and enable rapid clinical diagnosis.
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