Because most normal tissues express an isoform of pyruvate kinase other than PKM2, selective targeting of PKM2 provides an opportunity to target cell metabolism for cancer therapy.
It has two forms, COX-1, which is found in most normal tissues, and COX-2, which is induced in the presence of inflammation.
Tumor hypoxia refers to the development of regions within solid tumors in which the oxygen concentration is lower (0 3%) compared to that in most normal tissues (4 9%) (Vaupel and Hockel, 2000).
The accessibility and abundance of EDA in majority of the tumors and its absence in most normal tissues has made EDA a useful target for therapeutic intervention that has led to the development of IST-9 antibody that selectively blocks EDA accessibility to integrins and thus prevents metastasis.
A low uptake of radioactivity was noted in most normal tissues except for the bones.
Generally, COX-2 is not detectable in most normal tissues, but it is induced by pro-inflammatory cytokines, growth factors and carcinogens.
Up-regulation of hypoxia-inducing factor-1 (HIF-1) occurs in the majority of primary malignant tumors and in two-thirds of metastases, while most normal tissues are negative.
PSMA is abundantly expressed on the surface of prostate cancer cells and within the neovasculature of other solid tumors, with limited expression in most normal tissues, establishing the basis for selective targeting of PCa lesions with PSMA-targeted agents.
Particularly, literatures have reported that the microvascular permeability of most normal tissues was generally less than 50 nm, but ten times higher in tumor tissues and usually more than 500 nm.
It is also found at high to moderate levels in the kidney, brain, lung, and breast carcinomas, while it occurs at very low levels in most normal tissues (Kamen and Smith 2004).
Because most normal tissues generally do not express B7-H1, thatapies that block the protein could be specific to the melanoma cells, and expression of the protein could be used as a biomarker for patients who may respond to the therapies, the researchers say.
