Methylation and expression analysis of mismatch repair genes in extramammary Paget's disease.

BACKGROUND: Extramammary Paget's disease (EMPD) is a rare skin cancer with relative high frequencies of germline and somatic mismatch repair (MMR) genes mutations. However, the methylation and expression of these genes have not been validated in EMPD. OBJECTIVE: This study aims to confirm the methylation and expression of MMR genes in EMPD. METHODS: Immunohistochemical (IHC) staining detection and Methylation-specific PCR (MSP) were used to analyse MLH1, MSH2, MSH6 and PMS2 proteins' expression and promoters' methylation in 57 EMMD samples, and pyro-sequence was used to find highly methylated CpG sites in MSH2 promoter. RESULTS: Immunohistochemical detection displayed reduced expression of MSH2 in 38.6% EMPD cases but normal expression of MLH1, MSH6 and PMS2 in all tumour tissues. Hypermethylation also was found in the promoter of MSH2 but not in other MMR genes. Pyrosequencing of MSH2 promoter showed CpG6 (-87) and CpG3 (-98) were the most common two methylated CpG dinucleotides. There is a significant correlation between reduced MSH2 expression and MSH2 methylation. CONCLUSION: Reduced MSH2 expression and hypermethylation in this gene promoter were common genetic changes in EMPD, which expands our understanding of the role of MMR function in this skin cancer.

The number of regular T cells and immature dendritic cells involved in mycosis fungoides is linked to the tumor stage.

BACKGROUND: The balance between immune surveillance and immune escape determines the outcome of patients with primary mycosis fungoides (MF). FOXP3+ regulatory T cells (Tregs) and DC-SIGN+ immature dendritic cells (imDCs) play a central role in regulating the immune state in the progression of MF. However, whether the mechanisms used by these factors depend on MF stage is still underdetermined and even controversial. PATIENTS AND METHODS: FOXP3+ Tregs and DC-SIGN+ imDCs were detected by immunohistochemical staining of formalin-fixed, paraffin-embedded specimens obtained from the lesion biopsies of 89 patients with MF, comprising 69 patients at the patch stage, 12 at the plaque stage, and 8 at the tumor stage. The number of FOXP3+ Tregs and DC-SIGN+ imDCs in each stage was counted and compared. RESULTS: The expression of FOXP3 and DC-SIGN varied with the MF stage. The number of cells expressing FOXP3 was higher at the patch and plaque stages than at the tumor stage (p < 0.05), but no significant difference was noted between the patch and plaque stages (p = 0.715). DC-SIGN expression increased continuously, concomitant with tumor progression, through the three stages (p < 0.05). CONCLUSIONS: The predominant factor influencing the immune state is different for each MF stage. Therefore, therapeutic strategies that modulate the antitumor immune responses should be developed depending on MF progression.

Studies on the utilization of a plant SCE test in detecting potential mutagenic agents.

In this paper a modified procedure for sister-chromatid differentiation in plant cells is reported. Using this procedure some chemicals were tested for SCE induction in Vicia faba, Hordeum vulgare and Secale cereale. The chemicals tested were ethanol, chromium oxide, sodium saccharin, fluorouracil, ascorbic acid (vitamin c), omethoate and phenol. The experimental results showed that most of them induced SCE increases in mouse spleen cells, human lymphocytes and plant cells. The increase of SCEs per cell in plant cells is in agreement with that found in human lymphocytes or in mouse spleen cells. In our opinion, the utilization of SCE in plants is a simple and inexpensive technique for detecting potential mutagenic agents in the environment.