Cancer stem cells in colorectal cancer and the association with chemotherapy resistance.

The incidence and mortality of colorectal cancer (CRC) have always been among the highest in the world, although the diagnosis and treatment are becoming more and more advanced. At present, the main reason is that patients have acquired drug resistance after long-term conventional drug treatment. An increasing number of evidences confirm the existence of cancer stem cells (CSCs), which are a group of special cells in cancer, only a small part of cancer cells. These special cell populations are not eliminated by chemotherapeutic drugs and result in tumor recurrence and metastasis after drug treatment. CSCs have the ability of self-renewal and multidirectional differentiation, which is associated with the occurrence and development of cancer. CSCs can be screened and identified by related surface markers. In this paper, the characteristic surface markers of CSCs in CRC and the related mechanism of drug resistance will be discussed in detail. A better understanding of the mechanism of CSCs resistance to chemotherapy may lead to better targeted therapy.

Polymorphism in the Vesicular Monoamine Transporter 2 Gene Decreases the Risk of Parkinson's Disease in Han Chinese Men.

Background. Polymorphisms rs363371 and rs363324 in the vesicular monoamine transporter 2 (VMAT2) gene have been associated with risk of PD in an Italian population, and our aim is to investigate the association between the two single-nucleotide polymorphisms and PD in Han Chinese. Methods. 561 Han Chinese PD patients and 491 healthy age- and gender-matched controls were genotyped using Ligase detection reaction (LDR) method. Result. Both of patient and control groups showed similar genotype frequencies between patients and controls at both rs363371 and rs363324, as well as similar minor A allele frequencies at rs363371 (P = 0.452) and rs363324 (P = 0.413). None of the observed haplotypes showed a significant association with PD. Subgroup analysis by gender and age at onset revealed a significant association between the A allele of rs363371 and PD in Han Chinese males relative to healthy controls (OR 0.799, 95% CI 0.665 to 0.959, P = 0.016), and this association remained significant after adjusting for age (OR 0.785, 95% CI 0.652 to 0.945, P = 0.011). Conclusion. These results suggest that polymorphism of VMAT2 locus is associated with risk of PD in Han Chinese overall but that the A allele at rs363371 may protect against PD in Han Chinese males.

SNP rs7684318 of the alpha-synuclein gene is associated with Parkinson's disease in the Han Chinese population.

Mutations in the alpha-synuclein (SNCA) gene have been shown to be responsible for a rare familial form of Parkinson's disease (PD). Furthermore, polymorphic variants in multiple regions of the gene have been associated with susceptibility to idiopathic PD in different populations. Previous studies in Japanese have found a strong association between idiopathic PD and the single-nucleotide polymorphism (SNP) rs7684318, which is located within an intron of the SNCA gene. Our aim was to verify these findings and to further explore the nature of the association in a subset of Han Chinese PD patients. A case-control study of the SNP rs7684318, comprising 332 PD patients and 300 healthy controls, was carried out in Han Chinese populations from two centers in mainland China. The rs7684318 polymorphism was determined by PCR-restriction fragment length polymorphism (PCR-RFLP) analysis. The SNP rs7684318 of the SNCA gene showed a strong association with PD (P<0.01). Among our PD patients, mean age at disease onset and gender did not differ significantly between rs7684318 carriers and non-carriers. Our findings suggested that the SNP rs7684318 (T>C) transition of the SNCA gene contributes to PD susceptibility in Chinese Han population, which is consistent with the earlier study form Japan.