RESUMO
PURPOSE: Inactivation of the genes involved in DNA mismatch repair (MMR) is associated with microsatellite instability (MSI) and loss of heterozygosity (LOH). The aim of the current study was to assess the presence of MSI and promoter hypermethylation of MLH1 and MSH2 in Bulgarian PATIENTS WITH SPORADIC COLORECTAL CANCER (CRC) AND TO ANALYZE THEIR POSSIBLE EFFECT ON THE DEVELOPMENT, PROGRESSION AND PROGNOSIS OF THE DISEASE. METHODS: We examined MSI in 126 patients with sporadic CRC and the methylation status of the MLH1 and MSH2 promoter regions in the cases with MSI/LOH by using a panel of 5 microsatellite markers (BAT26, D5S346, D18S35, D2S123 and FGA) and methyl-specific PCR (MSP) of bisulfite converted DNA. RESULTS: MSI/LOH was found in 36 (28.6%) patients. Among them, 30 were analyzed for promoter hypermethylation of MLH1 and we detected hypermethylation in 15 (50%) of them, whereas promoter hypermethylation of MSH2 was observed only in one case. The presence of MSI/LOH was associated with younger age (p=0.002), more advanced stage (III/IV stage) (p=0.029), lower degree of differentiation (p=0.001), and right-sided tumor localization (p=0.0002), but not with overall survival (log rank, p=0.566). CONCLUSION: Our data suggest that sporadic CRCs with MSI/LOH are more aggressive, develop earlier and progress faster to more advanced stage. The most frequent cause of failure of DNA MMR system appeared to be the hypermethylation of CpG islands of the promoter region of MLH1, whereas the methylation of MSH2 was a rare event.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Neoplasias Colorretais/genética , Metilação de DNA , Instabilidade de Microssatélites , Proteína 2 Homóloga a MutS/genética , Proteínas Nucleares/genética , Regiões Promotoras Genéticas/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Colorretais/patologia , DNA de Neoplasias/genética , Feminino , Humanos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Proteína 1 Homóloga a MutL , Estadiamento de Neoplasias , Reação em Cadeia da Polimerase , Taxa de Sobrevida , Resultado do TratamentoRESUMO
Two i.v. regimens, bendamustine, methotrexate and 5-fluorouracil (BMF) and cyclophosphamide, methotrexate and 5-fluorouracil (CMF) were compared as first-line therapy in a randomized, open, multicenter phase III trial including 364 patients with metastatic breast cancer (MBC). Bendamustine is an anti-neoplastic agent with alkylating, but also additional, so far unclear, mechanisms of action. We wanted to show the superiority of BMF over CMF in terms of time to progression (TTP) (primary endpoint), overall response, response duration, toxicity and quality of life (QoL). TTP was significantly longer in the BMF group (8.2 versus 6.7 months for CMF) (p=0.0071). The effect of BMF on TTP was more pronounced in the stratum 'prior adjuvant therapy, no visceral metastases' (p=0.034). Overall response rates and QoL did not significantly differ between the regimens. BMF caused more mucositis and leukopenias. Thus, bendamustine, when replacing cyclophosphamide in the CMF combination, can be expected to produce longer progression-free survival in first-line treatment of MBC.