Human papillomavirus in esophageal squamous cell carcinoma in Colombia and Chile.

AIM: To examine the presence of human papillomavirus (HPV) in esophageal squamous cell carcinoma (ESCC) specimens collected from Colombia and Chile located in the northern and southern ends of the continent, respectively. METHODS: We examined 47 and 26 formalin-fixed and paraffin-embedded ESCC specimens from Colombia and Chile, respectively. HPV was detected using GP5+/GP6+ primer pair for PCR, and confirmed by Southern blot analysis. Sequencing analysis of L1 region fragment was used to identify HPV genotype. In addition, P16(INK4A) protein immunostaining of all the specimens was conducted. RESULTS: HPV was detected in 21 ESCC specimens (29%). Sequencing analysis of L1 region fragment identified HPV-16 genome in 6 Colombian cases (13%) and in 5 Chilean cases (19%). HPV-18 was detected in 10 cases (21%) in Colombia but not in any Chilean case. Since Chilean ESCC cases had a higher prevalence of HPV-16 (without statistical significance), but a significantly lower prevalence of HPV-18 than in Colombian cases (P = 0.011) even though the two countries have similar ESCC incidence rates, the frequency of HPV-related ESCC may not be strongly affected by risk factors affecting the incidence of ESCC. HPV-16 genome was more frequently detected in p16 positive carcinomas, although the difference was not statistically significant. HPV-18 detection rate did not show any association with p16 expression. Well-differentiated tumors tended to have either HPV-16 or HPV-18 but the association was not statistically significant. HPV genotypes other than HPV-16 or 18 were not detected in either country. CONCLUSION: HPV-16 and HPV-18 genotypes can be found in ESCC specimens collected from two South American countries. Further studies on the relationship between HPV-16 presence and p16 expression in ESCC would aid understanding of the mechanism underlying the presence of HPV in ESCC.

Risk factors of gastric cancer specific for tumor location and histology in Cali, Colombia.

AIM: To examine histology- and tumor-location specific risk factors of gastric cancer (GC). METHODS: This was a case-control study. The study subjects were 216 GC patients newly diagnosed during the period 2000-2002 and 431 controls selected from non-cancer patients matching in age, gender, and hospital. We obtained information on lifestyles, dietary habits, and others by a questionnaire. RESULTS: The subjects who were not eldest among his/her siblings were at a slightly elevated GC risk (OR 1.3; 95% CI 0.8-2.0). Salting meals before tasting was related to an increased GC risk (OR 3.5; 95% CI 1.6- 7.3). Frequent consumptions of fruits (OR 0.3; 95% CI 0.1-1.0) and vegetables (OR 0.3; 95% CI 0.1-1.0) were related to decreased GC risks. On the other hand, frying foods (OR 1.9; 95% CI 1.0-3.6) and cooking with coal (OR 1.8; 95% CI 1.3-2.6) were related to increased GC risks. Neither Laurenos histological classification (intestinal and diffuse types) nor tumor location significantly affected those associations except birth order. The subjects who were not eldest among his/her siblings had an increased risk of GCs in the distal and middle thirds, and their ORs were 1.7 (95% CI 1.0-2.8) and 1.9 (95% CI 0.8-4.3), respectively. The corresponding OR in the upper third stomach was 0.3 (95% CI 0.1-0.9). The differences of those three ORs were statistically significant (P = 0.010). CONCLUSION: The present study shows that birth order, salt intake, consumption of fruits and vegetables, the type of cooking, and cigarette smoking are related to GC risk. In histology and tumor-location specific analyses, non-eldest person among their siblings is related to an increased GC risk in the distal and middle thirds of the stomach, and is related to a decreased GC risk in the cardia.

Environmental factors related to gastric cancer associated with Epstein-Barr virus in Colombia.

Epstein-Barr virus (EBV)-encoded small RNA can be detected in about 1-17 % of gastric carcinomas. To elucidate lifestyles and other factors related to such an EBV-associated gastric carcinoma (EBV-GC), we conducted a case-control study in Cali, Colombia. The study subjects were 368 patients with gastric carcinoma newly diagnosed during the period between September 2000 and June 2003, including 42 EBV-GC cases. We obtained information on lifestyles, dietary habits, and occupational exposure by a questionnaire. The frequency of EBV-GC was related to birth order of patients (P for trend =0.025). More precisely, EBV-GC was much less frequent among the patients who were the eldest child in a family (P=0.007). Those findings were contrary to what was reported by the study conducted in Japan, where EBV-GC was more frequently observed among eldest brothers/sisters. A possible explanation for the apparently conflicting results is that EBV-GC risk is related to the age at first EBV infection but its relationship is not monotonic. In addition to the relationship with birth order, the present study showed that high salt intake and metal dust exposure may be related to EBV-GC as reported by the Japanese study although these associations observed in the present study were not statistically significant. No significant association was observed in other factors, including dietary habits. Further studies seem warranted to elucidate the difference between Japan and Colombia with respect to the environmental factors related to EBV-GC cases.

Epstein-Barr virus-associated gastric carcinoma: Evidence of age-dependence among a Mexican population.

AIM: To investigate features of Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC) among a Mexican population. METHODS: Cases of primary gastric adenocarcinoma were retrieved from the files of the Departments of Pathology at the Instituto Nacional de Cancerologia and the Instituto Nacional de la Nutricion in Mexico City. The anatomic site of the gastric neoplasia was identified, and carcinomas were histologically classified as intestinal and diffuse types and subclassified as proposed by the Japanese Research Society for Gastric Cancer. EBV-encoded small non-polyadenylated RNA-1 (EBER-1) in situ hybridization was conducted to determine the presence of EBV in neoplastic cells. RESULTS: We studied 330 consecutive, non-selected, primary gastric carcinomas. Among these, there were 173 male and 157 female patients (male/female ratio 1.1/1). EBER-1 was detected in 24 (7.3%) cases (male/female ratio: 1.2/1). The mean age for the entire group was 58.1 years (range: 20-88 years), whereas the mean age for patients harboring EBER-1-positive gastric carcinomas was 65.3 years (range: 50-84 years). Age and histological type showed statistically significant differences, when EBER-1-positive and -negative gastric carcinomas were compared. EBER-1 was detected in hyperplastic- and dysplastic-gastric mucosa surrounding two EBER-1-negative carcinomas, respectively. CONCLUSION: Among Latin-American countries, Mexico has the lowest frequency of EBVaGC. Indeed, the Mexican population >50 years of age was selectively affected. Ethnic variations are responsible for the epidemiologic behavior of EBVaGC among the worldwide population.

Epstein-Barr virus-associated gastric carcinoma in Cali, Colombia.

To estimate the incidence of Epstein-Barr virus-associated gastric carcinoma (EBV-GC) in Colombia and to clarify its clinicopathological features, we examined 178 consecutive gastric carcinoma cases, diagnosed during the period from 1996 to 1998, at Hospital Universitario del Valle in Cali, Colombia. The mean age of the cases was 60 years in males and 58 years in females. Using in situ hybridization assay of EBV-encoded small RNA-1 in paraffin-embedded tissue samples, we identified 23 cases of EBV-GC (13%). After excluding remnant carcinoma, which was found to be EBV-negative in this series, there were 19 (18%) male and 4 (6%) female EBV-GC cases, and the male predominance was statistically significant (P=0.004). The proportion of EBV-GCs decreased with age (P for trend = 0.022). Using sex- and age-specific proportions of EBV-GCs estimated by logistic models and gastric cancer incidence in Cali, which was obtained from tumor registry during the period 1987-1991, we estimated sex- and age-specific incidence of EBV-GCs. The incidence of EBV-GCs (per 100,000 person-years) was 4.1 and 1.4 among men and women, respectively, after age adjustment using the standard world population. Pathological features of EBV-GCs were also examined. EBV-GCs accounted for 33% (8/24) of carcinomas located in the stomach cardia, 14% (6/43) of carcinomas in the middle-part of the stomach, and 7% (6/81) of carcinomas in the antrum. The difference by tumor location was statistically significant (P=0.009). Histology-specific analysis using Lauren classification revealed that the proportion of EBV-GCs was not different in intestinal- and diffuse-type carcinomas (13% in both types). When the classification scheme of the Japanese Research Society for Gastric Cancer was used, EBV-GCs were identified more frequently in moderately differentiated tubular adenocarcinoma, and solid poorly differentiated adenocarcinoma when compared to other histological types. No lymphoepitelioma-like histology was found in the present series. The frequency of EBV-GC was slightly higher in advanced tumors, which involved serosa. Further analysis of clinico-pathological features of EBV-GC using a larger number of cases would give invaluable insights into its etiology.