Determinants of Epstein-Barr virus-positive gastric cancer: an international pooled analysis

BACKGROUND

Meta-analyses of the published literature indicate that about 9% of gastric cancers contain Epstein-Barr virus (EBV), with consistent and significant differences by sex and anatomic subsite. This study aimed to identify additional determinants of EBV positivity and their joint effects.

METHODS

From 15 international populations with consistent laboratory testing for EBV, we pooled individual-level data for 5081 gastric cancer cases including information on age, sex, subsite, histologic type, diagnostic stage, geographic region, and period of diagnosis. First, we combined population-specific EBV prevalence estimates using random effects meta-analysis. We then aggregated individual-level data to estimate odds ratios of EBV positivity in relation to all variables, accounting for within-population clustering.

RESULTS

In unadjusted analyses, EBV positivity was significantly higher in males, young subjects, non-antral subsites, diffuse-type histology, and in studies from the Americas. Multivariable analyses confirmed significant associations with histology and region. Sex interacted with age (P=0.003) and subsite (P=0.002) such that male predominance decreased with age for both subsites. The positivity of EBV was not significantly associated with either stage or time period.

CONCLUSION

Aggregating individual-level data provides additional information over meta-analyses. Distinguishing histologic and geographic features as well as interactions among age, sex, and subsite further support classification of EBV-associated gastric cancer as a distinct aetiologic entity.

Down regulation of gastric and intestinal phenotypic expression in Epstein-Barr virus-associated stomach cancers

AIMS

We have previously demonstrated the importance of gastric and intestinal phenotypic expression for stomach carcinogenesis. In this study, we focused on Epstein-Barr virus (EBV)-associated stomach cancers, with special attention to Cdx2.

METHODS AND RESULTS

We evaluated the expression of gastric and intestinal phenotypic markers by immunohistochemistry in 35 EBV-positive [EBV (+)] and 75 EBV-negative [EBV (-)] stomach cancers in Colombia. The lesions were divided phenotypically into gastric (G), gastric-and-intestinal mixed (GI), intestinal (I), and null (N) phenotypes. In the EBV (+) cases, the lesions were divided phenotypically into 9 G (25.7%), 1 GI (2.9%), 3 I (8.6%), and 22 N (62.9%) types. Similarly, the EBV (-) lesions were also classified phenotypically as 15 G (20.0%), 19 GI (25.3%), 24 I (32.0%), and 17 N (22.7%) types. The proportion of N type EBV (+) lesions was higher than for their EBV (-) counterparts (P<0.0001). The expression of Cdx2 and MUC2 was also found to be significantly lower in EBV (+) than in EBV (-) stomach cancers (P=0.0001; P<0.0001). Cdx2 expression in the intestinal metaplastic glands present in non-neoplastic mucosa surrounding EBV (+) lesions was also significantly lower than in EBV (-) tumors (P=0.016) despite no evidence of EBV infection.

CONCLUSIONS

EBV (+) stomach cancers are characterized by low expression of intestinal phenotype markers, including Cdx2, and only occasional gastric phenotypic expression.

Melanocyte reservoir in vitiligo

BACKGROUND

Dopa-negative, inactive melanocytes, present in the middle portion of the hair follicle, but also in hair bulbs, have been reported as a source of pigment cells, when repopulation of epidermal melanocytes occurs. A melanocyte reservoir in these anatomical sites has been suggested. Our objective was to investigate the ability of the lower third of the hair follicle (hair bulb) to repigment achromic skin in vitiligo.

METHODS

Scalp hair bulbs were transplanted within leukodermic areas in 10 patients with vitiligo.

RESULTS

Repigmentation around the grafts was suitable for evaluation in four cases. Dopa-positive (+) cells were seen in the epidermal basal cell layer of the repigmented areas.

CONCLUSIONS

Although these findings were observed only in a few patients, they suggest that melanocytes from the implanted lower third portion of the hair follicle (hair bulb) act as a reservoir in this anatomic location and are able to migrate and repigment achromic areas in vitiligo.

Gastric heterotopic mucosa in the rectum with Helicobacter pylori-like organisms: a rare cause of rectal bleeding

We report the case of a 9-year-old boy who presented with chronic rectal bleeding. On proctosigmoidoscopy, a polypoid elevation in the rectal ampulla measuring 5 x 3 cm was found. Biopsies were reported to show gastric mucosa. The Giemsa stain showed Helicobacter pylori-like organisms. Including our patient, there are now 30 similar cases reported in the medical literature. The usual manifestations of this rare entity are chronic bleeding and rectal pain. In one-half of cases there is chronic rectal ulceration. The recommended treatment is transanal surgical resection unless there is rectal peptic ulceration. H2 receptor blockers are then advised. Surgical excision is carried out after healing has taken place.

Leukoderma punctata

Thirteen patients with vitiligo (1 segmental, 4 focal, 8 generalized) aged 7 to 38, most of them female children, developed numerous punctate hypopigmented and achromic spots. The spots measured 0.5 to 1.5 mm and were located primarily on the sun-exposed areas of the extremities; they appeared following treatment with PUVASOL. Two of these patients experienced a reduction of this leukodermic defect, whereas the remaining patients showed a stable clinical course. Dopa and Fontana stains disclosed, in most cases, decreased but not absent functional melanocytes and a marked reduction of melanin. Ultrastructural studies demonstrated slight to severe damage of keratinocytes and melanocytes similar to that previously reported in vitiligo patients. The phototoxic effect of PUVASOL therapy is suggested as a possible etiologic factor in these patients. A probable relationship among idiopathic guttate hypomelanosis, leukoderma punctata, and vitiligo is discussed.

Morphology of the primary posterior plexus of the rat cochlear nucleus

Golgi impregnation results confirm the existence of a plexus (previously described with horseradish peroxidase tracing techniques) located in the posteroventral cochlear nucleus. The bulk of axons involved in this plexus could be traced to their origin in the root, and were not related to the V-bifurcating fibres, though some of the posterior branches of the latter contributed to the plexus. The internal structure of the plexus, and the different types of endings are described. These findings are discussed in relation to previous Golgi studies, especially those referring to the neuron and axon population of this area.

Leiomyomatosis peritonealis disseminata. An ultrastructural study

Electron microscopic features of the eighth documented case of leiomyomatosis peritonealis disseminata identify the main proliferative cell type as a mature leiomyocyte with all its associated ultrastructural features. The histogenesis of this neoplasm is considered to be a multicentric metaplastic change determined by an abnormal tissue response to the elevated hormonal levels occurring in pregnancy or ovarian functioning tumors. It is suggested that the cell of origin is the multipotent subcelomic mesenchymal cell, which retains the capacity to differentiate into several tissues, among them smooth muscle. To illustrate this possibility, myofibroblasts, cells with hybrid characters of fibroblasts and leiomyocytes, were observed; these may represent a transitional stage between the mesenchymal cell and the smooth muscle proliferating cell.