Biomedical subjects

Miguel Villaseca

Publications and source records attributed to Miguel Villaseca.

8 recordsLinked to original sources

PubMed2006

[Immunohistochemical expression of the E-cadherin-catenin complex in gastric cancer].

BACKGROUND: The E-cadherin/catenin complex plays an essential role in the control of epithelial differentiation. Abnormal expression in tumors correlates with histological grade, advanced stage and poor prognosis. AIM: To evaluate the expression pattern of E-cadherin/catenin complex in gastric carcinoma and analyze their association with tumor clinicopathological features and patient survival. MATERIAL AND METHODS: Inmunohistochemical staining of E-cadherin, alpha and ss-catenin was performed from paraffin specimens of 65 gastric carcinomas. RESULTS: Abnormal expression of E-cadherin, alpha and ss-catenin was demonstrated in 82%, 85% and 88% of gastric carcinomas, respectively. There was a significant correlation between abnormal expression and Lauren pathological classification and depth of infiltration, but not with tumor stage, positive lymph node metastases and survival. CONCLUSION: Abnormal expression of E-cadherin, alpha and ss-catenin occurs frequently in gastric carcinoma and correlates with histological grade.

Cadherins↗

PubMed2005

[Promoter methylation profile in gastric cancer].

BACKGROUND: Promoter genomic DNA methylation is an important inactivation mechanism of tumor suppressor genes. This genetic-molecular pathway for cancer may separate a subset of patients with different prognoses and eventually different responses to specific therapies. AIM: To analyze the methylation pattern of important genes related to different carcinogenic mechanisms in patients with gastric cancer (GC) and the relationship with its morphological features and biological behavior. MATERIAL AND METHODS: Forty-seven fresh-frozen GC samples were selected. The methylation-specific PCR (MSP) test was used to analyze promoter methylation status for genes MLH1, CDKN2A (p16), APC, CDH1 (Cadherin E) and FHIT. Follow-up and complete morphological features were obtained for all cases. RESULTS: We found methylation in at least one of the genes studied in 83% of the cases. The frequencies of promoter hypermethylation of MLH1, CDKN2A, APC, CDH1 and FHIT were 31%, 43%, 46%, 80% y 62%, respectively. We found a relationship between APC methylation and good histological differentiation (p =0.03); CDH1 methylation with diffuse type by Lauren and 3 or more metastasic lymph nodes (p <0.05); FHIT, CDKN2A and CDH1 methylation and female condition (p <0.04). We also found a non-significant relationship between CDKN2A methylation and better survival (p =0.07). CONCLUSIONS: The high frequency promoter methylation found confirms its importance in gastric carcinogenesis. The finding of alterations in the methylation pattern of genes studied and its association with prognostic factors is a helpful tool in the search for new criteria in clinical and therapeutic decision making.

Adult↗

PubMed2005

Microsatellite instability in preneoplastic and neoplastic lesions of the gallbladder.

BACKGROUND: Gallbladder cancer is very common in Chile and is the leading cause of cancer deaths in women aged over 40 years. However, there is limited information about the molecular changes involved in its pathogenesis. Microsatellite analysis was performed using polymerase chain reaction (PCR)-based assays to identify genetic loci that were altered in neoplastic and preneoplastic conditions of early and advanced gallbladder cancer. Our findings were then correlated with clinicopathological variables and survival time. METHODS: We selected 59 surgical specimens of gallbladder adenocarcinomas (29 early cancers and 30 advanced cancers) and 22 surgical specimens from patients with chronic cholecystitis from a high-risk area for gallbladder cancer (Temuco, Chile). Laser capture microdissection (LCM) was used to harvest tumor cells and preneoplastic lesions. Microsatellite analysis was performed using 13 different markers. The tumors and preneoplastic lesions were also examined with immunohistochemistry for hMLH1, hMSH2, and hMSH6. RESULTS: We found that 10% (6/59) of gallbladder cancers showed high-frequency microsatellite instability (MSI-H), with identical proportions in both early and advanced cancers. In premalignant lesions adjacent to the six MSI-H tumors, we detected instability in two of six examples of intestinal metaplasia (33%) and five of six examples of dysplasia (83%). All MSI-H cases showed an altered pattern with the antibodies studied. MSI status was not associated with survival or other clinicopathological features. No MSI or immunohistochemical alterations were found in the chronic cholecystitis group. CONCLUSIONS: Microsatellite instability was observed in equal proportions in early and late cancers, and it was also found in premalignant lesions, indicating that inactivation of mismatch repair genes occurs early in gallbladder carcinogenesis.

Adenocarcinoma↗

PubMed2004

[Promoter methylation profile in breast cancer].

BACKGROUND: Genomic DNA methylation, mutations and allelic deletions explain the inactivation of genes involved in cell proliferation and cell cycle control mechanisms. AIM: To analyze the methylation pattern of important genes related to different carcinogenic mechanisms in patients with breast cancer and the relationship with its biological behavior. MATERIAL AND METHODS: Seventy fresh-frozen breast cancer samples were selected. The methylation specific PCR (MSP) test was used to analyze promoter methylation status for genes CDKN2A (p16), hMLH1, APC, CDH1 (Cadherin E) and FHIT. RESULTS: We found methylation in at least one of the genes studied in 88% of cases and in 3 or more genes in 40.5% of cases. The frequencies of promoter hypermethylation of CDKN2A, hMLH1, APC, CDH1 and FHT were 41.4%, 11.4%, 52.9%, 70% and 42.9%, respectively. We found a relationship between CDKN2A methylatlon and better survival (p=0.002). CDH1 methylation and poor histological differentiation (p=0.007), hMLH1 methylation and non-Mapuche ethnicity (p=-0.03), APC methylation and larger tumor size (p<0.05), FHIT methylatton and lack of estrogen rectptor IHC expression (p<0.05). CONCLUSIONS: The high frequency of promoter methylation in patients with breast cancer confirms its role in breast carcinogenesis. The finding of alterations in the methylation pattern of genes studied and its association with prognostic factors is a helpful tool in the search of new criteria for clinical and therapeutic decision making.

Acid Anhydride Hydrolases↗

PubMed2004

[Inactivation of CDKN2A gene (p16) in gallbladder carcinoma].

BACKGROUND: The CDKN2A gene encodes a cyclin dependent kinase inhibitor, p16, which promotes cell cycle arrest. Methylation of the promoter region transcriptionally inactivates the gene. AIM: To study the relationship between methylation status of the prometer region of p16 gene, the immunohistochemical expression of p16 and clinical and morphological features of gallbladder carcinoma. MATERIAL AND METHODS: We analyzed the methylation status of the promoter region of the CDKN2A gene in gallbladder adenocarcinomas using methylation specific PCR (MSP). We also used microsatellite markers near the CDKN2A gene to detect allelic imbalance (AI) and examined the tumors by immunohistochemistry (IHC) for p16 expression. RESULTS: Of 38 gallbladder adenocarcinomas analyzed by IHC, 11 cases (29%) were negative for p16 protein. Nine (24%) had methylation of the promoter region of the CDKN2A gene. Twenty nine cases were negative for methylation, but four (14%) of these 29 exhibited AI at one or more of the microsatellite markers. CDKN2A promoter methylation was not associated with microsatellite instability (MSI-H). CONCLUSIONS: The inactivation of CDKN2A by methylation and/or deletion might play an important role in gallbladder carcinogenesis.

Adult↗

PubMed2002

[Morphological prognostic elements in gallbladder cancer].

BACKGROUND: The exact survival rates and prognostic factors of gallbladder cancer are still incompletely known. AIM: To report the actuarial survival of patients with gallbladder cancer. MATERIAL AND METHODS: Six hundred thirty seven women, aged 59 years old as a mean and 108 men, aged 64 years old as a mean, with gallbladder cancer are reported. Patients were followed for up to 150 months. RESULTS: Two hundred twenty four patients had an early and 521 had an advanced carcinoma. Overall survival was 38% at ten years. Sex or ethnic origin did not influence survival. Early tumors had a 92% survival at 10 years whereas the survival of advanced tumors was 16% at 5 years. Subserous tumors had a 5 years survival of 32% whereas serous tumors had a 5 years survival of 11%. Well-differentiated advanced tumors had a significantly better survival than moderately or poorly differentiated tumors. Vascular or lymphatic infiltration was also associated to a lower survival. All patients with advanced tumors and vascular infiltration died before 5 years. CONCLUSIONS: Tumor infiltration and differentiation degree were the most important prognostic independent factors in gallbladder cancer.

Adenocarcinoma↗

PubMed2002

[Is gallbladder cancer a disease with bad prognosis?].

Gallbladder cancer is frequent in Chile, but it is not uniformly mortal. The diagnosis is usually made after a cholecystectomy, indicated for a symptomatic cholelithiasis. Global survival of gallbladder cancer can be as high as 40% at five years. In 69% of women of less than 30 years old, the tumor is detected in early stages. In these cases, cholecystectomy is the curative procedure, with a 90% survival at five years. According to our experience, cholecystectomies should be performed between 40 and 50 years of age in men and between 30 and 40 years in women. The prognostic factors that should be considered are symptoms associated to lithiasis, age, parity, obesity, size of stones and the size of the gallbladder. If the tumor is detected in early stages, the survival is good. The natural history of the disease would change significantly if all women with symptomatic stones were operated.

Adult↗

PubMed2002

[Subserous gallbladder carcinoma: expression of cadherine-catenine complex].

BACKGROUND: Subserous gallbladder carcinoma is difficult to diagnose and treat. There are no tissue markers with prognostic value in this type of tumor. AIM: To study the immunohistochemical expression of E-cadherin alpha and beta catenin in subserous gallbladder carcinoma. PATIENTS AND METHODS: One hundred seventeen subjects (103 women and 14 men aged 62 and 69 years as a mean, respectively), were studied. Thirty five gallbladder samples without evidence of cancer were used as controls. Expression of markers was studied with standard immunohistochemical techniques for formalin fixed and paraffin embedded tissue. RESULTS: Ninety seven percent of tumors were adenocarcinoma. A lower or absent expression of E-cadherin, alpha catenin and beta catenin was observed in 26, 33 and 29% of tumors, respectively. Actuarial five years survival was 37%. No association between macroscopic features of the tumor and survival was observed. Well differentiated tumors had a 73% survival, whereas less differentiated tumors had a 30% survival. Tumors with a normal expression of the markers had a slightly better survival, although not significant (p = 0.06). CONCLUSIONS: Approximately 30% of subserous gallbladder carcinoma have an abnormal expression of E-cadherin, alpha catenin and beta catenin. This abnormal expression has no relationship with prognosis and is probably secondary to the aberrant genic expression of the tumor.

Adult↗