Research

Chromosomal radiosensitivity of lymphocytes in South African breast cancer patients of different ethnicity: An indirect measure of cancer susceptibility

F Z Francies, O Herd, X Muller, A Cairns, M Murdoch, M Nietz, J P Slabbert, A Baeyens

Abstract


Background. Breast cancer is the leading cancer among South African (SA) women. SA has citizens from diverse ethnic groups, and the lifetime risk of breast cancer differs according to ethnicity. Candidate genes for increased breast cancer risk are those involved in DNA damage repair pathways, and mutations in these genes are characterised by increased chromosomal radiosensitivity. Several European studies have shown that breast cancer patients are more sensitive to ionising radiation than healthy individuals.

Objectives. To investigate the in vitro chromosomal radiosensitivity of SA women with breast cancer and the possible influence of ethnicity and clinical parameters on chromosomal radiosensitivity.

Methods. Chromosomal radiosensitivity was analysed with the micronucleus assay using lymphocytes of breast cancer patients and healthy individuals of different ethnic groups. Lymphocytes were irradiated in vitro with 2 Gy or 4 Gy, and micronuclei (MN) were scored 70 hours after irradiation. These MN frequencies were correlated with the ethnicity and clinical parameters of the breast cancer patients.

Results. MN values were higher in breast cancer patients than in healthy controls. This was noted for black and white breast cancer patients at the different radiation doses. No correlations could be demonstrated between MN values and clinical parameters of the breast cancer, except that MN values were significantly higher in oestrogen receptor (ER)-positive breast cancers.

Conclusion. SA breast cancer patients have elevated chromosomal radiosensitivity compared with healthy controls. ER positivity also influences chromosomal radiosensitivity.


Authors' affiliations

F Z Francies, iThemba LABS/National Research Foundation, Somerset West, Western Cape, South Africa; Radiobiology, Department of Radiation Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa

O Herd, iThemba LABS/National Research Foundation, Somerset West, Western Cape, South Africa

X Muller, iThemba LABS/National Research Foundation, Somerset West, Western Cape, South Africa

A Cairns, Department of Surgery, Donald Gordon Medical Centre, Johannesburg, South Africa

M Murdoch, Department of Surgery, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa

M Nietz, Department of Surgery, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa

J P Slabbert, iThemba LABS/National Research Foundation, Somerset West, Western Cape, South Africa

A Baeyens, iThemba LABS/National Research Foundation, Somerset West, Western Cape, South Africa; Radiobiology, Department of Radiation Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa

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Keywords

Chromosomal radiosensitivity; Lymphocytes; Breast cancer; Ethnicity

Cite this article

South African Medical Journal 2015;105(8):675-678. DOI:10.7196/SAMJnew.8266

Article History

Date submitted: 2015-02-20
Date published: 2015-09-21

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