ABSTRACT
Background: The mitochondrial DNA (mtDNA) 10398 polymorphism is hypothesised to alter a mitochondrial subunit of the electron transfer chain and is associated with several neurodegenerative disorders and cancers. Methods: In this study, an mtDNA polymorphism at nucleotide position 10398 was screened in 101 Malay female patients with invasive breast cancer and 90 age-matched healthy female controls using minisequencing analysis. Results: The Malay women with the 10398G variant showed a significantly increased risk of invasive breast cancer (OR = 2.29, 95% CI 1.25–4.20, P = 0.007). Immunohistochemistry analysis was conducted to investigate the effect of this polymorphism on the levels of apoptosis in breast cancer cells. The level of Bax (a pro-apoptotic protein) expression was significantly higher than that of Bcl-2 (an anti-apoptotic protein) in patients carrying the G allele (P = 0.016) but not in those carrying the A allele (P = 0.48). Conclusion: Based on these findings, we propose that the mtDNA 10398 polymorphism may be a potential risk marker for breast cancer susceptibility in the Malay population.
ABSTRACT
Background: An unidentified animal species named the Jenglot and claimed to be a rare living animal species was recently found in the deep jungle of Irian Jaya, Indonesia; brought to Kuala Lumpur, Malaysia by a businessman; and exhibited in a local museum. The owner of the Jenglot carcasses had made a request to perform DNA analysis on the Jenglot to ascertain its species. Methods: Because the muscle appeared very dry and recovery of DNA was extremely difficult, we therefore used the animals’ hair for further analysis. Hair samples were collected from three different Jenglots that were different in colour and physical appearance. The samples were labelled as A, B, C and D, respectively. Results: Microscopic characteristics indicated that all four hair samples were of human origin, with a medullary index less than 1/3 and pigment distribution towards the periphery. The scale pattern on the hair samples was of the imbricate type, adding certainty to the hypothesis of human origin. A dried root sheath was found in samples B and C, which was contrary to expectations since the sample collection method left a few cm of hair on the body of the Jenglots. Sample D had black dye granules over the cuticular surface. Sequencing of the mitochondrial DNA (mtDNA) hypervariable segment I (HVS-I) region showed polymorphisms at positions 16140, 16182C, 16183C, 16189, 16217 and 16274 and heteroplasmy at positions 16112, 16232 and 16251, a human-specific mtDNA haplotype that was consistent across all the samples. Conclusions: Based on these findings, it was concluded that it is unlikely that the samples of Jenglot hair originated from an animal species.