Factores morfológicos asociados al pronóstico de pacientes operados por cáncer gástrico incipiente / Pathological features associated with survival in early gastric cancer

Background: Early gastric cancer corresponds to those tumors that only involve mucosa and submuco-sa. It is associated with a high survival rate. Aim: To determine pathological factors associated with survival in early gastric cancer. Material and Methods: Analysis of pathological records of 106 patients, with a median age of 63 years (60 percent> males), subjected to a gastrectomy for early gastric cancer. Follow up was performed according to data in the clinical records and death certificates obtained at the Chilean National Death Registry. Results: Five years global survival of patients was 91 percento. Lymph node involvement was more common among tumors bigger than 35 mm, with a low degree of differentiation and among those tumors classified as diffuse according to Lauren. Survival was significantly lower for bigger tumors, those with of a low degree of differentiation, diffuse tumors according to Lauren and those with lymph node involvement. Conclusions: Early gastric cancer has a high five years survival. Bigger tumors, those with a low degree of differentiation and those with lymph node involvement are associated with lower survival rates.

Introducción: El cáncer gástrico incipiente (CGI) es aquel que compromete la mucosa o submucosa gástrica independientemente del compromiso ganglionar linfático, estimándose su prevalencia en Chile inferior al 20 por cientoo. El objetivo de este estudio es determinar prevalencia de CGI y asociación de variables biode-mográficas y morfológicas con la supervivencia (SV) de pacientes resecados por CGI. Material y Método: Estudio de cohorte retrospectiva. Se estudiaron variables biodemográficas y morfológicas de 106 pacientes resecados por CGI entre 1986-2007. Se aplicó estadística descriptiva y analítica; confección de curvas de SV, y finalmente se aplicaron modelos de regresión logística para realizar ajuste, calcular odds ratio y sus respectivos intervalos de confianza de 95 por ciento. Resultados: 15 por ciento correspondió a CGI. La mediana de edad fue 63 años y el 60 por ciento correspondió a género masculino con una SV global a 5 años de 91 por ciento. Se observaron diferencias estadísticas significativas entre tumores mucosos y submucosos en cuanto a la localización tumoral y compromiso linfonodal junto con presentarse el compromiso nodal más frecuentemente en tumores > 35mm poco diferenciados y difusos de Lauren. El análisis multivariado identificó como factores asociados a la SV: tamaño tumoral, grado de diferenciación histológica en su variedad poco diferenciado, tipo difuso de Lauren y compromiso ganglionar linfático. Conclusiones: Se verificó una prevalencia de CGI de 15 por ciento, los que resecados presentan SV de 91 por ciento a 5 años. El compromiso linfonodal es un factor asociado a la SV; y además, se relaciona con tamaño tumoral, tipo histológico según Lauren, grado de diferenciación histológico y nivel de infiltración.

Detección y tipificación de virus papiloma humano en lesiones preneoplásicas de cuello uterino / Human papillomavirus genotyping of cervical uterine preneoplastic lesions in a high risk area

The relationship between human papillomavirus (HPV) and uterine cervical cancer (UCC) is widely known and accepted. Aim: To determine the frequency of genotypes of HPV in cervical preneoplastic lesions in a high risk area of UCC. Material and Methods: Using a combination of PCR and Reverse Line Blot technique, 235 formalin fixed paraffin embedded samples, with diagnosis of low-grade squamous intraepithelial lesion (LSIL) or high-grade squamous intraepithelial lesion (HSIL) were genotyped. Results: HPV was detected in 61.2 percent of LSIL and 78.1 percent of HSIL. The main genotypes found were HPV 16, 18, 31, 45, 56 y 58. HPV 16 was the most common in both LSIL (18.1 percent) and HSIL (36.9 percent). HPV 16 or 18 were present in 25.1 percent and 47.1 percent of the LSIL and HSIL respectively. In both LSIL and HSIL, the predominant viral genotypes were those types classified as with a high oncogenic risk. Conclusions: HPV genotypes 16, 18, 31, 45, 56 y 58 were the most common in our series. HPV 16 and 18, viral types with high oncogenic risk and included in commercial vaccines, were found in 25.1 percent and 47.1 percent of LSIL and HSIL, respectively.

Genotipificación del virus papiloma humano en mujeres con adenocarcinoma cervical de la Región de La Araucanía-Chile / Human papillomavirus genotyping in cervical adenocarcinoma in the Region of La Araucanía-Chile

El virus papiloma humano (VPH) es el principal factor causal del cáncer cervicouterino (CCU). Así, detectar y genotipificar el VPH es importante para conocer la frecuencia de los genotipos presentes en la región. En este trabajo se estudiaron 44 biopsias de adenocarcinoma cervical (ACC). Para la detección del VPH se empleó una reacción de polimerasa en cadena anidada dirigida al gen L1 (RPCL1), para la genotipificación viral se utilizaron enzimas de restricción (Rsa I, Dde I, Pst I) y secuenciación. Se detectó ADN viral mediante RPCL1 anidada en 100 por ciento de las biopias. Se logró tipificar 38/44 casos: 81,6 por ciento VPH 16; 13,2 por ciento VPH 18; 2,6 por ciento VPH 33 y 2,6 por ciento VPH 18/33. Conclusiones: La metodología fue exitosa para identificar el tipo viral en 86 por ciento de las biopsias. Se observó una estrecha asociación ACC-VPH, especialmente con el tipo viral 16, detectado en 81,6 por ciento de los casos tipificados.

Human papillomavirus (HPV) is the main cause of cervical cancer. Thus, HPV detection and typing becomes important in order to know the frequency of genotypes present in the region. In this paper we studied 44 biopsies of cervical adenocarcinoma. For HPV detection nested polymerase chain reaction (PCR) was used to amplify the L1 gene. For viral typing restriction enzymes (Rsa I, Dde I, Pst I) and DNA sequencing were used. Viral DNA was detected by nested L1 PCR in 100 percent of biopsies; 38/44 cases could be typed: 81.6 percent HPV16; 13.2 percent HPV 18; 2.6 percent VPH 33 and 2.6 percent HPV 18/33. Conclusions: The technique was successful in identifying the virus type in 86 percent of biopsies. There was a strong association ACC-HPV, especially with the viral type 16, detected in 81.6 percent of established cases.

Alteraciones genéticas en lesiones preneoplásicas y neoplásicas de la vesícula biliar / Genetic alterations in preneoplastic and neoplastic injuries of the gallbladder

This article aims to review the most relevant morphological and molecular aspects involved in gallbladder (GB) cancer. In Chile, gallbladder cancer is the main cause of death due to cancer, among women older than 40 years. However, there is almost none information about the morphological changes and the genetic alterations in-volved in the beginning and development of this neoplasia. Two carcinogenic ways have been described. The sequence adenoma-carcinoma is accepted to be less frequent and important. The most important is the sequence where a metaplasia evolves to displasia that progresses to carcinoma in situ and fnally it becomes invasive. This progress requires 10 to 15 years approximately. During this time, a continue progression of injuries have been described. Molecular research studies show genetic anomalies in some genes which are temporary events in preneoplastic injuries of the gallbladder. Some of them even exist before the frst morphological changes, while the expression of tumor suppressor genes like p53, adhesion molecules and oncogenes, among others, can be related to late GB carcinogenesis. The K-ras gene seems to play a role in this neoplasia, mainly in those that present an abnormal biliopancreatic union. The microsatelital instability has been found in a small subset of preneoplastic and neoplastic lesions. The existence of methylation in the promotor gene areas has been related to the cellular proliferation, invasion and metastasis and also in cases of chronic cholecystitis, suggesting that this epigenetic phenomenon represents a crucial early event in GB carcinogenesis.

[Human papillomavirus genotyping of cervical uterine preneoplastic lesions in a high risk area]. / Detección y tipificación de virus papiloma humano en lesiones preneoplásicas de cuello uterino.

BACKGROUND: The relationship between human papillomavirus (HPV) and uterine cervical cancer (UCC) is widely known and accepted. AIM: To determine the frequency of genotypes of HPV in cervical preneoplastic lesions in a high risk area of UCC. MATERIAL AND METHODS: Using a combination of PCR and Reverse Line Blot technique, 235 formalin fixed paraffin embedded samples, with diagnosis of low-grade squamous intraepithelial lesion (LSIL) or high-grade squamous intraepithelial lesion (HSIL) were genotyped. RESULTS: HPV was detected in 61.2% of LSIL and 78.1% of HSIL. The main genotypes found were HPV 16, 18, 31, 45, 56 y 58. HPV 16 was the most common in both LSIL (18.1%) and HSIL (36.9%). HPV 16 or 18 were present in 25.1% and 47.1% of the LSIL and HSIL respectively. In both LSIL and HSIL, the predominant viral genotypes were those types classified as with a high oncogenic risk. CONCLUSIONS: HPV genotypes 16, 18, 31, 45, 56 y 58 were the most common in our series. HPV 16 and 18, viral types with high oncogenic risk and included in commercial vaccines, were found in 25.1% and 47.1% of LSIL and HSIL, respectively.

[Detection and genotyping of human papillomavirus in biopsies of uterine cervical adenocarcinoma]. / Detección y tipificación de virus papiloma humano en adenocarcinoma de cuello uterino mediante reverse line blot, Región de La Araucanía, Chile.

BACKGROUND: The genotyping of Human Papillomavirus (HPV) will improve knowledge about the local epidemiological association of this virus with adenocarcinoma. AIM: To determine the frequency of HPV genotypes in biopsies of women with uterine cervical adenocarcinoma in a geographic region of Chile. MATERIALS AND METHODS: Forty-one cervical biopsies with a pathological diagnosis of adenocarcinoma, corresponding to all women diagnosed with this cancer between 2002 and 2004, were analyzed. Viral gene Ll was amplified by PCRfor viral detection. HPV genotyping was carried out by a Reverse Line Blot technique. RESULTS: Seventy one percent of biopsies were positive for HPV. The most common genotypes found were HPV 16 (61%), followed by HPV 18 (19.5%). Eighty seven percent of biopsies had a single HPV infection. Three patients had a multiple HPV infection. All of the latter were infected by HPV 16, associated with other three viral genotypes (45, 52 and 66). No low-risk HPV genotypes were found. CONCLUSIONS: In this sample of biopsies, there was a high prevelence of HPV 16 and a low prevalence of HPV 18, which historically has been related to adenocarcinoma. The genotypes found correspond to those described in South America.

Detección y tipificación de virus papiloma humano en adenocarcinoma de cuello uterino mediante reverse line blot, Región de La Araucanía, Chile / Detection and genotyping of human papillomavirus in biopsies of uterine cervical adenocarcinoma

Background: The genotyping of Human Papillomavirus (HPV) will improve knowledge about the local epidemiological association of this virus with adenocarcinoma. Aim: To determine the frequency of HPV genotypes in biopsies of women with uterine cervical adenocarcinoma in a geographic region of Chile. Materials and Methods: Forty-one cervical biopsies with a pathological diagnosis of adenocarcinoma, corresponding to all women diagnosed with this cancer between 2002 and 2004, were analyzed. Viral gene Ll was amplified by PCRfor viral detection. HPV genotyping was carried out by a Reverse Line Blot technique. Results: Seventy one percent of biopsies were positive for HPV. The most common genotypes found were HPV 16 (61 percent), followed by HPV 18 (19.5 percent). Eighty seven percent of biopsies had a single HPV infection. Three patients had a multiple HPV infection. All of the latter were infected by HPV 16, associated with other three viral genotypes (45, 52 and 66). No low-risk HPV genotypes were found. Conclusions: In this sample of biopsies, there was a high prevelence of HPV 16 and a low prevalence of HPV 18, which historically has been related to adenocarcinoma. The genotypes found correspond to those described in South America.

[Gene methylation patterns in digestive tumors]. / Estudio de patrones de metilación génica en tumores del tubo digestivo.

BACKGROUND: The loss of tumor suppressor gene function damages the defensive mechanisms that protect the indemnity of genetic material. Promoter gene methylation is one of the inactivation mechanisms of suppressor genes. AIM: To study the methylation pattern of a group of genes in biopsy samples of gastrointestinal tumors. MATERIAL AND METHODS: Forty eight gastric, 25 gallbladder, 24 colon and 6 pancreas cancer biopsy samples were randomly selected. The methylation pattern of CDH1, FHIT, CDKN2A, APC and MLH1 genes, was studied using a specific polymerase chain reaction test for methylation. Demographic, morphological and follow up variables of patients bearing the tumors were also analyzed. RESULTS: The general methylation frequency of CDH1, FHIT, CDKN2A, APC and MLH1 genes was 64.1, 56, 39.8, 18.1 and 34% respectively. In gastric cancer samples there was a correlation between APC gene methylation and well differentiated tumors; between CDH1 methylation and Lauren diffuse type and the presence of three or more metastasic lymph nodes; between FHIT, CDKN2A and CDH1 gene methylation and male gender. In less differentiated gallbladder tumors, the frequency of CDH1 methylation was higher. There was a tendency towards a lower survival in colon and gastric cancer when MLH1 (p =0.07) y CDKN2A (p= 0.06) were methylated, respectively. CONCLUSIONS: An abnormal methylation pattern was associated with morphological features in gastric and gallbladder cancer and with a tendency towards a lower survival in colon and gastric cancer.

Estudio de patrones de metilación génica en tumores del tubo digestivo / Gene methylation patterns in digestive tumors

Background: The loss of tumor suppresor gene function damages the defensive mechanisms that protect the indemnity of genetic material. Promoter gene methylation is one of the inactivation mechanisms of suppressor genes. Aim: To study the methylation pattern of a group of genes in biopsy samples of gastrointestinal tumors. Material and methods: Forty eight gastric, 25 gallbladder, 24 colon and 6 pancreas cancer biopsy samples were randomly selected. The methylation pattern of CDH1, FHIT, CDKN2A, APC and MLH1 genes, was studied using a specific polymerase chain reaction test for methylation. Demographic, morphological and follow up variables of patients bearing the tumors were also analyzed. Results: The general methylation frequency of CDH1, FHIT, CDKN2A, APC and MLH1 genes was 64.1, 56, 39.8, 18.1 and 34 percent respectively. In gastric cancer samples there was a correlation between APC gene methylation and well differentiated tumors; between CDH1 methylation and Lauren diffuse type and the presence of three or more metastasic lymph nodes; between FHIT, CDKN2A and CDH1 gene methylation and male gender. In ¡ess differentiated gallbladder tumors, the frequency of CDH1 methylation was higher. There was a tendency towards a lower survival in colon and gastric cancer when MLH1 (p =0.07) y CDKN2A (p= 0.06) were methylated, respectively. Conclusions: An abnormal methylation pattern was associated with morphological features in gastric and gallbladder cancer and with a tendency towards a lower survival in colon and gastric cancer.

Efecto de la fijación en la calidad del ADN: estudio controlado con cinco fijadores / Effect of fixation on DNA quality: controlled study with five fixatives

Antecedentes: Los tejidos fijados y embebidos en parafina son una fuente importante de material para diagnóstico e investigación. La amplificación de ADN desde este tipo de tejidos, mediante reacción en cadena de la polimerasa (PCR), es afectada por el tipo de fijador y los tiempos de fijación empleados. Para determinar el parámetro que mejor se adecue a las condiciones de trabajo de nuestro laboratorio de Patología Molecular, evaluamos el efecto de cinco fijadores sobre la calidad del ADN bajo condiciones controladas. Material y Método: Muestras de mucosa gástrica fueron fijadas, embebidas en parafina y luego procesadas para extracción de ADN empleando un protocolo basado en digestión con proteinasa K. La calidad del ADN se evaluó mediante amplificación de tres fragmentos del gen β-globina (268, 536 y 989 pb). Resultados: No observamos mayores diferencias entre fijadores ni tiempos de fijación en la amplificación de ADN de 268 y 536 pb. No obstante, la amplificación del fragmento mayor (981 pb) se vio alterada al aumentar el tiempo de fijación, a excepción de aquellas muestras fijadas en etanol 70% que presentaron una banda de similar intensidad a la obtenida para muestras control (tejido fresco congelado). Conclusiones: Estos resultados nos proporcionan una pauta para el diseño de experimentos de acuerdo a la calidad del material archivado, optimizando recursos humanos e insumos

Background: Fixed and paraffin-embedded tissues from pathological archives are an important source for research. DNA amplification by polymerase chain reaction (PCR) from those materials is affected by fixatives and fixation time. In order to determine the best condition for our laboratory work, we evaluated the effect of five different fixatives on DNA quality under controlled conditions. Material and Method: Gastric mucosa samples from two patients were fixed, embedded in paraffin and then processed for DNA extraction using a routine method based on proteinase K digestion. DNA quality was evaluated by amplifying three Beta-globin gene fragments (268, 536 and 989 bp). Results: We did not observe major differences among fixatives nor fixation times for 268 and 536 bp fragments but the amplification of the greatest fragment was altered by increasing the fixation time, by excepting those samples fixed in 70% ethanol which present a similar band intensity than control samples (snap-frozen tissue). Conclusions: These results give us a good guideline to design experiments considering the quality of our archival material