Necessity of Microdissecting Different Tumor Components in Pulmonary Tumor Pyrosequencing.
Microdissection is a useful method in tissue sampling prior to molecular testing. Tumor heterogeneity imposes new challenges for tissue sampling. Different microdissecting methods have been employed in face of such challenge. We improved our microdissection method by separately microdissecting the morphologically different tumor components. This improvement helped the pyrosequencing data analysis of two specimens. One specimen consisted of both adenocarcinoma and neuroendocrine components. When both tumor components were sequenced together for KRAS (Kirsten rat sarcoma viral oncogene homolog) gene mutations, the resulting pyrogram indicated that it was not a wild type, suggesting that it contained KRAS mutation. However, the pyrogram did not match any KRAS mutations and a conclusion could not be reached. After microdissecting and testing the adenocarcinoma and neuroendocrine components separately, it was found that the adenocarcinoma was positive for KRAS G12C mutation and the neuroendocrine component was positive for KRAS G12D mutation. The second specimen consisted of two morphologically different tumor nodules. When microdissected and sequenced separately, one nodule was positive for BRAF (v-raf murine sarcoma viral oncogene homolog B1) V600E and the other nodule was wild type at the BRAF codon 600. These examples demonstrate that it is necessary to microdissect morphologically different tumor components for pyrosequencing.
Department of Pathology, Moffitt Cancer Center, 12902 USF Magnolia Drive, Tampa, FL 33612, USA.
Dahui
0000-0001-9618-5836
D
Qin
Department of Pathology, Moffitt Cancer Center, 12902 USF Magnolia Drive, Tampa, FL 33612, USA.
Zhong
Z
Zheng
Department of Pathology, Moffitt Cancer Center, 12902 USF Magnolia Drive, Tampa, FL 33612, USA.
Shanxiang
S
Shen
Department of Pathology, Moffitt Cancer Center, 12902 USF Magnolia Drive, Tampa, FL 33612, USA.
Prudence
P
Smith
Department of Pathology, Moffitt Cancer Center, 12902 USF Magnolia Drive, Tampa, FL 33612, USA.
Farah K
FK
Khalil
D000230:Adenocarcinoma / Q000235:genetics; D002454:Cell Differentiation; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000601:surgery*; D042282:Microdissection / Q000379:methods*; D009154:Mutation / Q000235:genetics; D009490:Neurosecretory Systems / Q000473:pathology; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics; D017422:Sequence Analysis, DNA / Q000379:methods*; D013696:Temperature
C117307:KRAS protein, human; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D016283:Proto-Oncogene Proteins p21(ras)