Positive correlation between telomere length and mitochondrial copy number in breast cancers

Higher peripheral blood mitochondrial DNA copy number and relative telomere length in under 48 years Indonesian breast cancer patients

OBJECTIVE

Breast cancer is the leading cause of cancer incidence and mortality among Indonesian women. A comprehensive investigation is required to enhance the early detection of this disease. Mitochondrial DNA copy number (mtDNA-CN) and relative telomere length (RTL) have been proposed as potential biomarkers for several cancer risks, as they are linked through oxidative stress mechanisms. We conducted a case-control study to examine peripheral blood mtDNA-CN and RTL patterns in Indonesian breast cancer patients (n = 175) and healthy individuals (n = 181). The relative ratios of mtDNA-CN and RTL were determined using quantitative real-time PCR (qPCR).

RESULTS

Median values of mtDNA-CN and RTL were 1.62 and 0.70 in healthy subjects and 1.79 and 0.73 in breast cancer patients, respectively. We found a positive association between peripheral blood mtDNA-CN and RTL (p < 0.001). In under 48 years old breast cancer patients, higher peripheral blood mtDNA-CN (mtDNA-CN ≥ 1.73 (median), p = 0.009) and RTL (continuous variable, p = 0.010) were observed, compared to the corresponding healthy subjects. We also found a significantly higher 'High-High' pattern of mtDNA-CN and RTL in breast cancer patients under 48 years old (p = 0.011). Our findings suggest that peripheral blood mtDNA-CN and RTL could serve as additional minimally invasive biomarkers for breast cancer risk evaluation.

No association between telomere length and osteonecrosis of the femoral head

Background

Telemore length (TL) shortening has been found in many diseases. However, clinical characteristics of TL shortening in osteonecrosis of the femoral head (ONFH) has not been investigated. Therefore, we studied whether TL changes have clinicopathological values in ONFH.

Methods

The TL in the synovial tissues of 36 ONFH and 127 control patients (femoral neck fracture) was examined by quantitative real-time PCR as relative length, Δ Ct value. In addition, the correlation between TL and clinical features of ONFH and controls was analyzed.

Results

The average TL in the femoral tissues was 1.46 ± 3.12 (standard deviation). The average TL in the ONFH and control tissues was 1.92 ± 4.11 and 1.34 ± 2.78, respectively, however, the difference was absent (p = 0.324). Furthermore, a shorter TL was tended to be associated with erythrocyte sedimentation rate (100% vs. 61.5%, p = 0.073); however, the association was not statistically significant.

Conclusions

In this study, we demonstrated that there is no association between the TL and clinicopathologic characteristics of ONFH patients. However, further studies considering the genetic factors are needed to be performed.