Objectives: Circulating tumor DNA (ctDNA) is shown to provide the real-time genomic information of metastatic breast cancer. This study elucidates the clinico-pathological significance of ctDNA in early-stage breast c...Objectives: Circulating tumor DNA (ctDNA) is shown to provide the real-time genomic information of metastatic breast cancer. This study elucidates the clinico-pathological significance of ctDNA in early-stage breast cancer using the PIK3CA mutation as an indicator. Materials and Methods: Twenty-seven primary breast cancers without metastasis were surgically resected and pathologically diagnosed at the University of Tokyo Hospital, Japan. Genomic DNA of primary tumor was extracted from formalin-fixed and paraffin-embedded specimens. ctDNA was extracted from fresh-frozen plasma from patients. The PIK3CA mutations at E542K, E545K and H1047R were examined by Sanger sequencing or droplet digital PCR in 27 tumors and pre- and post-surgery plasma. Results: The PIK3CA mutations were detected in 13 (48%) of 27 primary tumors. These mutations did not significantly correlate with specific clinico-pathological characteristics of tumors. When ctDNA was examined, 4 (33%) of 12 cases carrying the mutated PIK3CA showed the identical mutation in pre-surgery plasma and 2 (50%) of them showed the identical mutations in post-surgery plasma. Interestingly, in these 2 cases in pathological stages IIIA and IA, fractional abundance of the mutated PIK3CA alleles to the total alleles in pre-surgery ctDNA was around 1% or more and was higher than that of the other two cases without PIK3CA mutations in post-surgery ctDNA. Conclusions: The PIK3CA mutation in ctDNA is detectable even in a subset of early-stage breast cancer. Furthermore, fractional abundance of the mutated PIK3CA in pre-surgery ctDNA could provide a possible predictive indicator for tumor burden and for choosing the appropriate adjuvant treatment of breast cancer.展开更多
Objective: Targeting mutated EGFR by EGFR-tyrosine kinase inhibitors (EGFR-TKI) is a potent approach to a subset of non-small cell lung cancer (NSCLC). However, the response to EGFR-TKI varies in individual cases even...Objective: Targeting mutated EGFR by EGFR-tyrosine kinase inhibitors (EGFR-TKI) is a potent approach to a subset of non-small cell lung cancer (NSCLC). However, the response to EGFR-TKI varies in individual cases even among tumors carrying the same?EGFR?mutation, suggesting the involvement of modifying factors. To characterize possible modifiers, we examined mutation state of the?EGFR?and the?KRAS?genes in Japanese NSCLC and compared them with the methylation state of lung tumor suppressors, the?CADM1 and?4.1B,?whose products have potentials to modify the functions of EGFR or KRAS. Materials and methods: A total of 103 Japanese NSCLC and 11 NSCLC cell lines were examined. Genomic DNA of exons 18–21 of the?EGFR?and exons 1 and 2 of the?KRAS?were amplified by polymerase chain reaction (PCR), followed by single-strand conformation polymorphism analysis and direct sequencing. Methylation status of gene promoters in NSCLC cells were examined by methylation-specific PCR. Results: Mutations of the?EGFR?and?KRAS?were detected mutually exclusively in 27 and 11 out of 103 NSCLC cases, respectively.?EGFR?mutations were observed exclusively in adenocarcinoma (27 of 69, 41%) and preferentially in tumors from female and non-smokers (p < 0.00001). Eight (30%) and 12 (44%) of 27 tumors carrying mutated?EGFR?and 4 (36%) and 8 (73%) of 11 tumors carrying mutated?KRAS?showed methylation of the?CADM1 and 4.1B, respectively.?EGFR-mutated tumors with methylation of either?CADM1 or 4.1B?showed more malignant features than those with unmethylated?CADM1 and 4.1B?(p < 0.05). Conclusion: Methylation state of the?CADM1 and?4.1B?are independent of the mutation status of the?EGFR?or?KRAS?but play roles in the malignant progression of NSCLC. Integration of epigenetic information would be useful for identifying possible modifiers to predict the response or recurrence of lung adenocarcinoma to the EGFR-TKI therapy.展开更多
文摘Objectives: Circulating tumor DNA (ctDNA) is shown to provide the real-time genomic information of metastatic breast cancer. This study elucidates the clinico-pathological significance of ctDNA in early-stage breast cancer using the PIK3CA mutation as an indicator. Materials and Methods: Twenty-seven primary breast cancers without metastasis were surgically resected and pathologically diagnosed at the University of Tokyo Hospital, Japan. Genomic DNA of primary tumor was extracted from formalin-fixed and paraffin-embedded specimens. ctDNA was extracted from fresh-frozen plasma from patients. The PIK3CA mutations at E542K, E545K and H1047R were examined by Sanger sequencing or droplet digital PCR in 27 tumors and pre- and post-surgery plasma. Results: The PIK3CA mutations were detected in 13 (48%) of 27 primary tumors. These mutations did not significantly correlate with specific clinico-pathological characteristics of tumors. When ctDNA was examined, 4 (33%) of 12 cases carrying the mutated PIK3CA showed the identical mutation in pre-surgery plasma and 2 (50%) of them showed the identical mutations in post-surgery plasma. Interestingly, in these 2 cases in pathological stages IIIA and IA, fractional abundance of the mutated PIK3CA alleles to the total alleles in pre-surgery ctDNA was around 1% or more and was higher than that of the other two cases without PIK3CA mutations in post-surgery ctDNA. Conclusions: The PIK3CA mutation in ctDNA is detectable even in a subset of early-stage breast cancer. Furthermore, fractional abundance of the mutated PIK3CA in pre-surgery ctDNA could provide a possible predictive indicator for tumor burden and for choosing the appropriate adjuvant treatment of breast cancer.
文摘Objective: Targeting mutated EGFR by EGFR-tyrosine kinase inhibitors (EGFR-TKI) is a potent approach to a subset of non-small cell lung cancer (NSCLC). However, the response to EGFR-TKI varies in individual cases even among tumors carrying the same?EGFR?mutation, suggesting the involvement of modifying factors. To characterize possible modifiers, we examined mutation state of the?EGFR?and the?KRAS?genes in Japanese NSCLC and compared them with the methylation state of lung tumor suppressors, the?CADM1 and?4.1B,?whose products have potentials to modify the functions of EGFR or KRAS. Materials and methods: A total of 103 Japanese NSCLC and 11 NSCLC cell lines were examined. Genomic DNA of exons 18–21 of the?EGFR?and exons 1 and 2 of the?KRAS?were amplified by polymerase chain reaction (PCR), followed by single-strand conformation polymorphism analysis and direct sequencing. Methylation status of gene promoters in NSCLC cells were examined by methylation-specific PCR. Results: Mutations of the?EGFR?and?KRAS?were detected mutually exclusively in 27 and 11 out of 103 NSCLC cases, respectively.?EGFR?mutations were observed exclusively in adenocarcinoma (27 of 69, 41%) and preferentially in tumors from female and non-smokers (p < 0.00001). Eight (30%) and 12 (44%) of 27 tumors carrying mutated?EGFR?and 4 (36%) and 8 (73%) of 11 tumors carrying mutated?KRAS?showed methylation of the?CADM1 and 4.1B, respectively.?EGFR-mutated tumors with methylation of either?CADM1 or 4.1B?showed more malignant features than those with unmethylated?CADM1 and 4.1B?(p < 0.05). Conclusion: Methylation state of the?CADM1 and?4.1B?are independent of the mutation status of the?EGFR?or?KRAS?but play roles in the malignant progression of NSCLC. Integration of epigenetic information would be useful for identifying possible modifiers to predict the response or recurrence of lung adenocarcinoma to the EGFR-TKI therapy.
