The phrase "normal tissue" refers to the healthy and usual cells that make up our bodies. It indicates that the tissue is not affected by any disease, injury, or abnormality. Full definition
This means that a wide area of normal tissue around the tumor will be removed so that no cancer cells can be detected under a microscope from the margins of the tissue extracted. (caninecancer.com)
Currently, molecular targets for cancer therapy must either be exclusively expressed by tumor cells or expressed at significantly higher levels in tumors than in normal tissues. (journals.plos.org)
Studies that compare genomic information from tumors and normal tissue from the same patient allow researchers to discover genomic changes that may drive cancer. (cancer.gov)