Thesis (Ph.D.) - Cairo University - Faculty of Medicine - Department of Clinical and Chemical Pathology

Backround: The D-loop is a hot spot for mitochondrial DNA (mtDNA) alterations and comprises two hypervariable regions (HVR1: np 16024{u2013}16383 and HVR2: np 57{u2013}372). Accumulation of D-loop alterations has been reported in breast cancer. Aim of the work: This study was performed to evaluate the association of mitochondrial DNA variants in a group of Egyptian patients with breast cancer and healthy controls adjusted for age. Subjects and methods: The present study examined the involvement of mitochondrial DNA regions (HVR-1 & HVR-2) in 50 breast cancer patients compared to 40 healthy controls in the Egyptian females. Results: The present study revealed that the region HVR-1 has shown 41 variants, the variants 16172T>C (p=0.034) [OR=7.429, 95%CI = 0.888-62.14], 16189T>C (p=0.006) [OR=11.0, 95%CI = 1.354-89.351] and 16223C>T (p<0.001) [OR=18.353, 95%CI = 2.311-145.73] have shown statistical significant difference with higher frequency in breast cancer cases than healthy controls. And the region HVR2 revealed 23 variants, only 73A>G has shown a statistically significant difference of (p=0.033) [OR=0.338, 95%CI= 0.120-0.954] with higher frequency in healthy controls (32.5%) than breast cancer patients (14%). And they have shown non-significant association with the clinicopathological features (histological subtype, grade, lymph node status, TNM staging of BC, the ER/PR status) except for the association of the variant 16223 C>T with duct carcinoma (p= 0.010). In conclusion, mitochondrial D-loop alterations could be of high value in detecting risk of development in breast cancer

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