Cáncer de vesícula biliar ¿la contaminación por bilis afecta el pronóstico? / Gallbladder Cancer: does bile contamination affect the prognosis?

Resumen Introducción: En algunas áreas el cáncer de la vesícula biliar se detecta en hasta el 3,5% de los pacientes intervenidos por colelitiasis. Con el objetivo de evaluar el rol de la ruptura de la vesícula y la consiguiente contaminación por bilis, se evaluó una serie de pacientes portadores de cáncer de vesícula diagnosticado posterior a la colecistectomía. Materiales y Método: El estudio se efectuó en 109 pacientes en quienes se diagnosticó un cáncer de vesícula posterior a la colecistectomía. El grupo a estudiar se dividió de acuerdo a la ocurrencia o no de contaminación por bilis al momento de la colecistectomía, como también de acuerdo a la magnitud de ésta. Resultados: De los pacientes estudiados, en 32 se documentó la ocurrencia de contaminación por bilis al momento de la colecistectomía. De estos, en 13 la contaminación fue considerada mayor. El tiempo promedio de seguimiento fue de 33 meses, 35 pacientes (32,1%) fallecieron durante el seguimiento. La sobrevida media de la totalidad de la serie que tuvo contaminación por bilis no se diferenció de los pacientes sin contaminación. Sin embargo, el grupo que tuvo una contaminación catalogada como mayor, presentó una sobrevida estadísticamente inferior al resto de los pacientes. Finalmente, se realizó un análisis mediante el modelo de regresión de COX que incluyó edad, género, nivel de invasión y tipo de contaminación, resultando la existencia de contaminación mayor por bilis un factor independientemente asociado al pronóstico. Conclusión: La presencia de ruptura vesicular y contaminación mayor por bilis debiera considerarse un factor pronóstico.

Background: Incidental gallbladder cancer is observed in up to 3.5% of patients undergoing laparoscopic cholecystectomy. To study the role of wall perforation on the prognosis, we evaluated a series of patients in whom perforation occurred during the cholecystectomy. Materials and Method: 109 patients who underwent a laparoscopic cholecystectomy in whom final diagnosis was gallbladder cancer were the focus of the study. We divided the patients according the occurrence of spillage. Furthermore, patients with spillage were divided into two categories according the spillage magnitude. Results: Of the patients, spillage was documented in 32 (29.3%). In 13 patients spillage was considered major. The median follow-up of patients was 36 months, while 35 (32.1%) patients died during the follow-up. Five-year survival of all patients with spillage was not statistically different from the group without spillage. However, the group with major spillage had a statistically worse survival than the rest. A Cox regression analysis including age, gender, level of invasion and spillage category showed that major spillage was independently associated with a worse prognosis.

Ictericia obstructiva secundaria a migración de fragmentos de hepatocarcinoma a la vía biliar / Obstructive jaundice secondary to hepatocellular carcinoma fragments migrated to common bile duct

Obstructive j aundice is a rare presentation of hepatocellular carcinoma (HC), and when it occurs, usually is due to progressive damage from cirrhosis, or extensive tumor infiltration. Tumor growth through the bile duct is being described with increasing frequency as a cause of obstructive j aundice. Rarely, it may be hepatocarcinoma fragments that migrate to the bile duct, obstructing it. We present a case of obstructive jaundice due to migration of fragments of hepatocellular carcinoma to the bile duct in a patient treated 7 years before, for an HC with a curative resection.

La ictericia obstructiva es una presentación poco común en un hepatocarcinoma (HC). Cuando en estos casos existe ictericia, habitualmente se debe a daño progresivo por cirrosis, o a infiltración tumoral extensa. El crecimiento o vaciamiento tumoral hacia la vía biliar se ha descrito ocasionalmente como causa de ictericia obstructiva. En raras ocasiones, puede tratarse de fragmentos de hepatocarcinoma que migran hacia la vía biliar, obstruyéndola. Presentamos un caso de ictericia obstructiva por migración de fragmentos de hepatocarcinoma a la vía biliar, en un paciente tratado 7 años antes por un HC, con resección curativa.

Colesterolosis y cáncer de la vesícula biliar / Association between cholesterolosis and gallbladder cancer

Background: Cholesterolosis is frequently observed in cholecystectomies performed for lithiasis or chronic cholecystitis. Aim: To determine the degree of association between cholesterolosis and gallbladder cancer. Material and Methods: In a prospective study of gallbladder cancer, all gallbladders obtained during cholecystectomies were processed for pathological study, following a special protocol. As part of this study, 23304 surgical samples obtained between 1993 and 2002 were studied, looking for a relationship between cholesterolosis and chronic cholecystitis, adenomas, dysplasia and gallbladder cancer. Results: Seventy nine percent of patients were women. Cholesterolosis was observed in 3,123 cases (13.4 percent). Cholesterolosis was more common in women (14.2 percent) than in men (10.2 percent) (p < 0.001). In the same period, 29 patients were diagnosed with adenomas (0.12 percent), 179 cases with dysplasia not associated with gallbladder cancer (0.8 percent) and 739 gallbladder cancer (3.2 percent). The frequency of cholesterolosis was 13.8 percent in chronic cholecystitis, 13.7 percent in adenomas, 12.1 percent in dysplasias and 1.35 percent in patients with gallbladder cancer (p < 0.01). Of the thirteen cases with gallbladder cancer and cholesterolosis, 10 were early gallbladder carcinomas. Patients with cholesterolosis were 9.2 times less likely to have cancer than those who did not have cholesterolosis. Conclusions: Cholesterolosis has a strong negative association with gallbladder cancer.

Carcinoma subseroso de la vesícula biliar (pT2): valor pronóstico de la expresión de los genes supresores de tumores p53 y p27 en matrices de tejidos / p53 and p27 gene expression in subserosal gallbladder carcinoma

Background: Subserosal carcinoma is the stage that presents the greatest difficulty in the diagnosis therapeutic handling and prognosis evaluation. Aim To study the expression of p53 and p27 genes in subserosal gallbladder cancer. Material and methods: One hundred twenty seven tissue samples of subserosal gallbladder cancer (coming from 112 females aged 62 ± 13years and 15 men aged 67 ± 17years) and 50 control samples were selected to construct tissue arrays. p53 andp27genes were determined by immunohistochemistry. Results: Thirty eight percent of tumors were not detected at the macroscopic examination, 52 percent and 17 percent had lymph node and blood vessel involvement, respectively. Fifty six and 46 percent were positive for p53 and p27, respectively. No association between the expression of both genes and gender, degree of differentiation, lymph node or blood vessel involvement, was observed. Overall five years actuarial survival was 32 percent. Patients with positive or negative p53 expression had a 22 percent and 53 percent survival, respectively (p =0.05). No association between survival and p27 expression was observed. Conclusions: p53 gene expression is a prognostic factor for subserosal gallbladder cancer.

Desde la displasia hasta el cáncer de la vesícula biliar / Natural history of gallbladder cancer Analysis of biopsy specimens

Background: There is scarcity of knowledge about the development of gallbladder cancer. Aim: To study the features of development and progression of gallbladder cancer. Material and methods: Review of histopathological studies of gallbladder obtained in 25,971 cholecytectomies performed in patients aged 45± 16 years, 79 percent females, between 1993 and 2004. Among these, 210 had a dysplasia not associated to cancer and 1,039 had a gallbladder cancer Clinical and morphological parameters of preneoplastic and neoplastic lesions were analyzed. Ninety five percent of patients were followed. Results: All cases of dysplasia were incidental findings. Metaplasia, dysplasia and carcinoma in situ were present in the adjacent mucosa in 66 percent, 81 percent y 69 percent of gallbladder carcinomas, respectively. Twenty five percent of gallbladders studied were carcinomas (mucous carcinoma in 18 percent and muscular carcinoma in 7 percent). Ninety two percent of cases had chronic inflammation in the gallbladder wall. Seventy two percent of mucous carcinomas were not detected macroscopically Five years survival of mucous carcinoma was 92 percent. There was an association between the intensity of the lesion and the age of the patients. The age difference between chronic cholecystitis and gallbladder cancer was 11 years for women and nine for men. Conclusions: From a morphological standpoint, the period in which a dysplasia becomes a carcinoma is approximately 10 years.

Proliferación celular en la mucosa de la vesícula biliar no tumoral en colecistitis crónicas litiásicas. Expresión de Ki-67 en matrices de tejidos / Immunohistochemical expression of Ki-67 as a marker of proliferation in gallbladder mucosa samples with or without cancer

Background: There is paucity of knowledge on the proliferative features of normal or chronically inflamed gallbladder and the mechanisms of development of gallbladder cancer. Aim: To study the proliferation features of non tumoral gallbladder mucosa through the expression of Ki-67 antigen in tissue micro array analysis. Material and methods: The immunohystochemical expression of Ki-67 in tissue micro array was studied in 96 samples of non tumoral gallbladder mucosa (coming from 74 females aged 45±16 years and 22 males aged 53±16 years) and 102 samples of gallbladder cancer (coming from 84 females aged 62± 14 years and 18 males aged 70± 13 years). Results: The staining index of Ki-67 expression was 19±25 percent (range 096-8996) in samples of non tumoral mucosa and 46±29 percent (range 396-9896) in gallbladder cancer (p <0.01). Ki-67 was expressed in less than 10 percent of epithelial cells in 55 percent of non tumoral mucosa samples and 6 percent of gallbladder cancer samples. Seventy five percent of gallbladder cancer samples had a staining index of more than 20 percent. An expression of Ki-67 over 20 percent or 50 percent was observed in 25 percent and 15 percent of non tumoral mucosa samples, respectively Conclusions: Non tumoral gallbladder mucosa samples have a high proliferation index, measured using Ki-67 immunohystochemical expression. There is a group of samples with cellular hyper-proliferation that maybe related to the pathogenesis of gallbladder cancer.

Banco de tumores en Chile, su aporte a la investigación: resultados de un proyecto piloto / A pilot experience with a tumor bank

Background: Despite having the technical facilities and the knowledge, Chile did not have a tumor bank until recently. Aimn: To describe the results of the first three years of a tumor bank. Material and methods: All cases stored in a tumor bank from June 2004 tojune 2007 were included. Samples were frozen in isopentane, afterwards in liquid nitrogen and finally transferred to freezers at -80°C. Quality controls with DNA and RNA extraction and immunohistochemistry, were per formed. Results: In the study period, 1239 cases were collected and 79 percent were malignant tumors. In 78 percent of cases, samples from the tumor and of normal neighaboring tissue, were stored. Twenty six percent of samples were from breast cáncer and 22 percent for digestive tumors. Immunohistochemical expression ofvimentin was measured in 30 cases and the expression of Ki67 an p53 in 20 cases. Thirteen of 15 breast cáncer samples had expression of estrogen receptors. In 30 cases, DNA and RNA extraction was carried out, amplifying B-globin and B-actin. Moreover RNA was extracted from 63 gastríc cáncer, 30 colon cáncer and gallbladder cáncer samples, for specific projects. Conclusions: The creation of a tumor bank is feasible, preserving samples of high biológical quality.

Inestabilidad microsatelital en lesiones preneoplásicas y neoplásicas del cuello uterino: Correlación con el genotipo del virus papiloma humano / Microsatellite instability and human papilloma virus genotypes in preneoplastic and neoplastic uterine cervix lesions

Background: The association between some specific human papilloma virus (HPV) types and cervix cancer is well known. However, the genetic conditions that favor the development of cervical cancer are less well known. Aim: To determine the presence of satellite instability (MSI) in preneoplastic and neoplastic lesions of the cervix and correlate these findings with HPV genotypes. Material and methods: Biopsy samples of cervical lesions were studied. Sixteen had low grade lesions, 22 had high grade lesions and 28 had an epidermoid cancer. Viral types were identified with polymerase chain reaction, dot-blot hybridization and restriction fragment length polymorphism. MSI was determined using a panel of eight highly informative microsatellites. Results: Microsatellite instability in at least one locus was observed in 91, 56 and 69 percent of low grade lesions, high grade lesions and epidermoid carcinomas, respectively. MSI-High grade, MSI-Low grade instability and microsatellite stability were observed in 5, 60 and 46 percent of samples, respectively. Two of three samples with high grade instability had HPV 52 genotype. Other viral subtypes had frequencies that ranged from 78 percent to 100 percent, with the exception of HPV16 that was present in only 53 percent of samples with low grade instability. Conclusions: Two thirds of biopsy samples from cervical lesions had MSI, mechanism that can be involved in the first stages of cervical carcinogenesis. The low frequency of high grade instability, its association with HPV52 and the low frequency of HPV16 in samples with low grade instability, suggest different coadjutant mechanisms in cervical carcinogenesis

Frecuencia de los genes de fusión TEL/AML1 y BCR/ABL en pacientes pediátricos con leucemia linfoblástica aguda / Frequency of TEL/AML1 and BCR/ABL fusion genes in children with acute lymphoblastic leukemia

Background: t(12;21) (p12;q22) and t(9;22) (q34;q11) translocations have prognostic significance in acute lymphoblastic leukemia (ALL). The fusion genes TEL/AML1 y BCR/ABL, generated by these translocations, can be easily detected using molecular biology technique. Aim: To study the frequency of TEL/AML1 y BCR/ABL fusion genes in children with ALL. Material and methods: Fifity six children with ALL (age range 1 month- 14 years) were studied, thirty eight from our Temuco Hospital and 18 from the Metropolitan Region. TEL/AML1 y BCR/ABL fusion genes were detected in bone marrow samples using a reverse transcriptase nested polymerase chain reaction (RT-PCR). Results: TEL/AML 1 and BCR/ABL fusion gene transcripts were detected in 13 (23 percent) and 2 (4 percent) children, respectively. No differences in survival were observed between children with positive or negative transcripts for TEL/AML1 fusion gene. However, those positive for BCR/ABL fusion gene, had a significantly lower survival. Conclusions: The frequency of TEL/AML1 and BCR/ABL fusion gene transcripts in these children with ALL is similar to that described by other authors.

Osteonecrosis asociada al uso de bifosfonatos: A propósito de un caso clínico / Osteonecrosis associated with the use of biphosphonates: Case report

Biphosphonates reduce the risk of skeletal events and are currently part of standards of therapy in myeloma. Recently, zoledronate and pamidronate have been linked to osteonecrosis of the jaw, specially after surgical dental procedures. We report a 84 year-old man with multiple myeloma who developed spontaneous osteonecrosis of both jaws, after 36 months of therapy with zoledronate with a cumulative dose of 136 mg. We discuss the pathogenic mechanisms, and review the recommendations on prevention and management of this new complication for neoplastic patients under prolonged therapy with biphosphonates.

Expresión inmunohistoquímica del complejo E-caderina-catenina en cáncer gástrico: Relación con variables clínico-morfológicas y sobrevida de pacientes / 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 percent, 85 percent and 88 percent 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.

Mutación del gen K-ras en tumores pancreático-biliares / Frequency of K-ras mutation in biliary and pancreatic tumors

Background: The ras gene family (H-ras, N-ras and K-ras) are oncogenes that mutate frequently in human cancer, specially in tumors of the biliary tract and pancreas. Aim: To determine the frequency of K-ras gene codon 12 mutation in pancreatic and biliary tumors. Material and Methods: Samples of 35 gallbladder, 15 ampulla of Vater, 10 biliary tract and 9 pancreatic tumors, were analyzed. The tumor tissue was microdissected from paraffin embedded biopsies. The mutation was detected by a combination of polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). Results: Overall, 46% of samples had K-ras gene mutations. Mutation frequency was 80, 56, 50 and 29% for ampulla of Vater, pancreatic, biliary tract and gallbladder tumors, respectively. When compared with the rest, gallbladder tumors had a significantly lower frequency of the mutation. Median survival for biliary tract tumors was 6 months, compared with 65 months for gallbladder tumors (p <0.05). Conclusions: Gallbladder carcinoma had the lower frequency of K-ras mutation, when compared with pancreatic, biliary tract and ampulla of Vater tumors.

Proposición de procesamiento de biopsias de la vesícula biliar, clasificación y etapificación del cáncer de la vesícula biliar / Gallbladder cancer: a proposal for management of biopsies, classification and staging

El cáncer de la vesícula biliar es una de las neoplasias más frecuentes en nuestro país. Su alta incidencia va acompañada de un mal pronóstico en los estadios avanzados de la enfermedad, por lo cual, el diagnóstico precoz pareciera ser una de las únicas posibilidades para modificar la historia natural de esta enfermedad. El diagnóstico de cáncer vesicular en la gran mayoría de los casos es posterior al estudio histológico de las colecistectomías y el estudio anatomopatológico es determinante, no sólo en establecer el diagnóstico del tumor, si no que precisar los elementos pronósticos de mayor importancia. De esta manera, el estudio rutinario de las piezas de colecistectomía cobra gran relevancia. En este trabajo se propone una forma de procesamiento de la vesícula biliar con y sin lesión tumoral. A través de un sencillo algoritmo es posible de acuerdo a la realidad nacional realizar un buen y completo estudio anatomopatológico de éste órgano, aportando importante información al cirujano y al paciente. Esta proposición requerirá de constante revisión producto de los nuevos hallazgos en el área de la cirugía, patología y biología molecular de esta neoplasia.

Estudio del patrón de metilación génico en el cáncer gástrico en Chile / 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.

Estudio comparativo de detección del virus papiloma humano (VPH) en muestras citológicas y biopsias de cuello uterino / Detection of human papilloma virus in cytologic samples or biopsies of the cervix

Background: The DNA quality for the detection and typification of Human Papilloma Virus (HPV) varies according to the type of sample in which it is studied. This may affect the sensitivity and specificity of the method employed. Aim: To study the yield and specificity of HPV detection and typification in uterine cervical samples obtained by cervical brushing fresh frozen and formalin fixed tissue. Material and methods: Cytological, fresh frozen and fixed tissue samples from 44 patients (nine with low grade lesions and 35 with high grade lesions) were studied. Nested polymerase chain reaction for genes E6/E7 was used to typify HPV groups as low risk or high risk. Results: Of all the cytological samples obtained by brushing 84% of fixed samples and 43% of fresh frozen samples were positive for HPV. The yields were significantly different when comparing brushing with fixed tissue or fresh frozen tissue and fixed tissue with fresh frozen tissue (p <0.05). The frequency of high risk HPV fluctuated from 41% in fresh frozen tissue to 98% in cytological samples. Low risk HPV was detected in 16% of fresh frozen tissue and 68% of cytological samples. A mixed infection was detected in 66%, 41% and 14% of cytological, fresh frozen and fixed tissue samples respectively. Conclusions: Cytological samples obtained by brushing had the highest yield for the detection of cervical infection with HPV.

Hiperparatiroidismo primario con compromiso esquelético grave: Un caso de carcinoma paratiroideo / Primary hyperparathyroidism with severe skeletal involvement in one patient with parathyroid carcinoma

Parathyroid carcinoma is an uncommon cause of primary hyperparathyroidism; however, when this condition is severe, cancer must be suspected. We report on a 28-year-old male with severe hypercalcemia, cachexia, acute pancreatitis, urolithiasis, anemia and a severe skelletal involvement with multiple fractures. The patient had a 4-cm parathyroid tumor, that was surgically excised, along with the ipsilateral thyroid lobe. During the postoperative period, he had a severe and prolonged hungry bone syndrome, with a slow recovery of fractures, with functional and anatomical sequelae in the extremities. PTH levels were adequate for the serum calcium during the 16 months of follow-up.

Detección de micrometástasis en médula ósea de pacientes con cáncer de vesícula biliar / Detection of bone marrow micrometastases in patients with gallbladder cancer

Background: There is a very strong documented correlation between the appearance of cancer cells in blood and occurrence of metastasis in gastrointestinal cancer. Aim: To determine MUC1, CK19, CK20 and CEA mRNA expression in bone marrow of patients with gallbladder cancer and evaluate its clinical significance. Material and methods: Sixty eight samples were analyzed, 38 bone marrow samples of gallbladder cancer patients, 20 healthy donors, and 10 frozen samples of gallbladder cancer. Nested reverse transcriptase-polymerase chain reaction (nested RT-PCR) was used to analyze mRNA expression. Results: All frozen tumors were positive for CEA, CK19, and MUC1 mRNA and 70 percent were positive for CK20. Seventeen of 20 donor samples were positive for MUC1 and only one sample from donors was positive for both CK20 and CK19 mRNA. Among the 38 blood and bone marrow samples of gallbladder cancer patients, the expression of MUC1, CK19, CK20, and CEA, mRNA was 60.5 percent (23/38), 31.6 percent (12/38), 7.9 percent (3/38), and 7.9 percent (3/38), respectively. Disregarding the MUC1 results. 37 percent (14/38), 13 percent (5/38) and 5 percent (2/38) were positive for one, two and three markers respectively. Not significant differences were found in survival with a follow up to 12 months. Conclusion: Our results indicate that the molecular detection of tumor cells in bone marrow in patients with gallbladder carcinoma is technically possible, being CEA, CK19 and CK20 gene expression the best markers. The MUC1 gene expression marker was highly unspecific and it should not been considered. The detection of bone marrow micrometastasis might be helpful in prognosis and the selection of clinical treatment but a larger series with a longer follow-up should be studied.

Relación de la genotipificación de Helicobacter pylori con la forma e intensidad de la gastritis en población adulta portadora de patología gástrica benigna / Association between helicobacter pylori genotype and the severity of gastritis in infected adults

Background: The damaging capacity of Helicobacter pylori is variable and depends, in part, on its genetic polymorphism. Aim: To study H pylori genes vacA, cagA and iceA and the relationship of these genotypes with the features of acute damage in chronic gastritis. Material and methods: Gastric endoscopic biopsies were obtained in 75 adults for pathological study and genetic typification of H pylori by specific PCR. Results: In only 64 cases, complete information was available. In 53 of these, there was H pylori infection demonstrated by PCR. Twenty one percent had infection by two or more H pylori strains, vacA gene had genotypes s2/m2, s1/m1 and s1/m2 in 36, 25 and 8% of cases respectively, cagA gene was present in 49% of infected patients. iceA gene had genotypes iceA 1 ad iceA 2 in 15 and 60% of patients respectively. The presence of cagA or alleles s1/m1 and s1/m2 of vacA gene was directly correlated with polymorphonuclear infiltration and the severity of epithelial damage. The genotype s2/m2 of vacA gene was significantly associated with a milder or absent mucosal damage. No association was found between iceA alleles and the pathological features of gastritis. Conclusions: Alleles of vacA and cagA genes of H pilory are associated with the severity of gastric mucosal damage.

Inactivación del gen CDKN2A (p16) en cáncer de la vesícula biliar / 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 trans-criptionally 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.

Mutación del gen K-ras en el cáncer de la vesícula biliar / K-ras gene mutation in gallbladder carcinoma

Background: Different K-ras mutation frequencies in gallbladder cancer have been reported. Aim: To study the frequency of K-ras gene mutations in advanced gallbladder carcinoma not associated to anomalous junction of pancreatic-biliary duct (AJPBD). Material and methods: 33 formalin fixed paraffin embedded samples of gallbladder carcinoma (30 women, age range 32-86 years) were selected. Pancreatic cancer tissue with K-ras mutations was used as control. DNA was extracted from the histological section by mean of microdissection and K-ras mutations in codon 12 were detected by polymerase chain reaction and restriction fragment length polymorphism (RFLP), using previously reported technique. Results: Most cases were poorly differentiated adenocarcinomas. K-ras mutation was detected in 10 cases (30%) samples. No differences in K-ras mutation frequency between subserous and serous tumors were detected and no relation between histological features and the mutation was observed. Conclusions: K-ras mutation in codon 12 is present in 30% in our advanced gallbladder carcinomas. The study of K-ras mutation in preneoplastic lesions and early carcinomas will be important to determine the role of this gene in the gallbladder carcinogenesis in Chile (Rev Méd Chile 2004; 132: 955-60).