【4.0.2】主干突变（trunk mutations）
在6个样本中，总共识别到1231个somatic mutations，将其中的210个nonsynonymous SNVs，
- 来自于所有的6个样本，并共同出现在35个mutation sites作为trunk mutation；
- 108个nonsynonymous SNVs，只在一个样本中出现，作为 private branch ；
- 剩下的64个nonsynonymous SNVs，在2-5个样本中出现，作为 branch mutations
研究对象是一名做过减积手术（tumor-reductive surgery）男性胃癌病人，对其切除的胃肿瘤在术后30分钟内按照顺时针方向取6个样本，然后进行WES测序（multiregional genome sequencing）；对分析得出的somatic nonsynonymous substitutions进行分类：trunk, branch, and private branch mutations，进而来评估胃癌的ITH
Trunk mutations are genetic alterations that occur early in the development of a tumor and are present in the majority of tumor cells. These mutations are considered “trunk” mutations because they are found in the ancestral lineage of the tumor cells and are shared by all subsequent daughter cells as the tumor grows and evolves.
The term “trunk” comes from the analogy of a phylogenetic tree, where the trunk represents the common ancestor and the branches represent the divergent evolutionary paths. In the context of cancer evolution, trunk mutations are the foundational genetic changes that drive tumorigenesis and are responsible for initiating the development of the tumor.
Understanding trunk mutations is crucial in cancer research and treatment because they can serve as diagnostic markers for identifying the origin and evolution of a tumor. Additionally, targeting trunk mutations may offer therapeutic opportunities to disrupt key oncogenic pathways driving tumor growth and progression.
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