Biomaterial Database

Heterogeneity in human tumour hypoxic fraction using the comet assay. 1996

P L Olive, and T Trotter, and J P Banáth, and S M Jackson, and J Le Riche

British Columbia Cancer Research Centre, Vancouver, Canada.

The alkaline comet assay has previously been used to estimate the fraction of radiobiologically hypoxic cells in tumours from patients undergoing palliative radiotherapy for advanced breast and head and neck cancer. Results obtained from fine needle aspirate biopsies (FNABs) using this method indicate considerable heterogeneity in hypoxic fraction between tumours. Heterogeneity between 3 aspirates taken from the same 10 tumours immediately following single doses of 3.5 to 5 Gy is now examined. Results indicate that a single fine needle aspirate is reasonably representative for DNA damage and DNA content. However, difficulties were encountered in obtaining an adequate sample of tumour cells after the final radiation treatment. The average hypoxic fraction decreased from 14% after the first dose to 9% after the last dose, and in 3 tumours which could be evaluated after both the first and last fraction, the hypoxic fraction decreased in two but increased in the third. Rejoining of DNA strand breaks was observed between sequential aspirates indicating that pooling of samples for analysis may not be advisable using this method.

UI	MeSH Term	Description	Entries
D009369	Neoplasms	New abnormal growth of tissue. Malignant neoplasms show a greater degree of anaplasia and have the properties of invasion and metastasis, compared to benign neoplasms.	Benign Neoplasm,Cancer,Malignant Neoplasm,Tumor,Tumors,Benign Neoplasms,Malignancy,Malignant Neoplasms,Neoplasia,Neoplasm,Neoplasms, Benign,Cancers,Malignancies,Neoplasias,Neoplasm, Benign,Neoplasm, Malignant,Neoplasms, Malignant
D004249	DNA Damage	Injuries to DNA that introduce deviations from its normal, intact structure and which may, if left unrepaired, result in a MUTATION or a block of DNA REPLICATION. These deviations may be caused by physical or chemical agents and occur by natural or unnatural, introduced circumstances. They include the introduction of illegitimate bases during replication or by deamination or other modification of bases; the loss of a base from the DNA backbone leaving an abasic site; single-strand breaks; double strand breaks; and intrastrand (PYRIMIDINE DIMERS) or interstrand crosslinking. Damage can often be repaired (DNA REPAIR). If the damage is extensive, it can induce APOPTOSIS.	DNA Injury,DNA Lesion,DNA Lesions,Genotoxic Stress,Stress, Genotoxic,Injury, DNA,DNA Injuries
D004273	DNA, Neoplasm	DNA present in neoplastic tissue.	Neoplasm DNA
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001707	Biopsy, Needle	Removal and examination of tissue obtained through a transdermal needle inserted into the specific region, organ, or tissue being analyzed.	Aspiration Biopsy,Puncture Biopsy,Aspiration Biopsies,Biopsies, Aspiration,Biopsies, Needle,Biopsies, Puncture,Biopsy, Aspiration,Biopsy, Puncture,Needle Biopsies,Needle Biopsy,Puncture Biopsies
D015687	Cell Hypoxia	A condition of decreased oxygen content at the cellular level.	Anoxia, Cellular,Cell Anoxia,Hypoxia, Cellular,Anoxia, Cell,Anoxias, Cell,Anoxias, Cellular,Cell Anoxias,Cell Hypoxias,Cellular Anoxia,Cellular Anoxias,Cellular Hypoxia,Cellular Hypoxias,Hypoxia, Cell,Hypoxias, Cell,Hypoxias, Cellular