Bovine upper alimentary squamous cell carcinoma associated with bracken fern poisoning: Clinical-pathological aspects and etiopathogenesis of 100 cases.

Tatiane Cargnin Faccin,Betina Fabis Lautert,Fernanda Rezer De Menezes,José Vitor Marcon Piazer,Fernando De Souza Rodrigues,Eduardo Furtado Flores,Stella Maris Pereira De Melo,Juliana Felipetto Cargnelutti,Glaucia Denise Kommers,Douglas H Thamm

doi:10.1371/journal.pone.0204656

Tatiane Cargnin Faccin, Betina Fabis Lautert + Show 8 more

Open Access

https://doi.org/10.1371/journal.pone.0204656

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Abstract

Upper digestive tract (UDT) cancer is rare in cattle, however in Southern Brazil, the UDT squamous cell carcinomas (SCCs) are relatively common and have been associated with bracken fern consumption and the presence of papillomas. Although a theory of pathogenesis considers bovine papillomavirus type 4 (BPV-4) as a cofactor in the development of these SCCs, some aspects of the etiopathogenesis of this disease need to be more investigated. In fact, detection of BPV-4 in UDT papillomas is scarce in other regions of the world and has not been performed in Brazil. Therefore, this study had two aims: 1) to analyze the epidemiological, clinical and pathological aspects of 100 natural cases of SCCs in the UDT of cattle grazing on bracken fern (Pteridium arachnoideum) highly contaminated areas, investigating the associations between these parameters; and 2) to investigate the presence of papillomavirus DNA by polymerase chain reaction (PCR) in the UDT papillomas (n = 47) from 30 cattle that also had UDT SCCs. There were statistically significant associations between clinical signs and tumor localization in the UDT; between histological grade of differentiation and tumor localization; and a trend towards significant association between histological grade of differentiation and presence of metastases. The average age of cattle with oropharyngeal SCCs was 7.39 years, with statistically significant difference comparing to cattle with esophageal SCCs (8.6 years). No statistical association was observed among other clinical-pathological parameters (growth pattern and primary site of the tumor) analyzed. No BPV DNA was detected in papillomas by PCR. Therefore, these results suggest the possibility that papillomas of the UDT are not necessarily associated with BPV infection.

Highlights

Squamous cell carcinomas (SCCs) are the most common oral neoplasms of humans, cats, horses, and livestock species and are the second most common of dogs, behind only the melanocytic tumors [1,2,3,4]
An exception is seen in a few geographic areas, such as Southern Brazil, where oral, pharyngeal, esophageal, and ruminal SCCs may represent around 20% of all neoplasia of cattle [6]
Some studies show that upper digestive tract (UDT) papillomas are caused by a productive bovine papillomavirus type 4 (BPV-4) infection [10, 11]

Summary

Introduction

Squamous cell carcinomas (SCCs) are the most common oral neoplasms of humans, cats, horses, and livestock species and are the second most common of dogs, behind only the melanocytic tumors [1,2,3,4]. An exception is seen in a few geographic areas, such as Southern Brazil, where oral, pharyngeal, esophageal, and ruminal SCCs may represent around 20% of all neoplasia of cattle [6]. In these regions, SCCs of the upper digestive tract (UDT) are associated with chronic bracken fern (Pteridium spp.) poisoning and presence of UDT papillomas [3, 5, 7,8,9]. Histological and electron microscopic data suggested a role of BPV-4 in the development of alimentary SCCs [7], and the disease has been experimentally reproduced [12], no BPV-4 DNA could be detected in almost all the SCCs tested by Southern blot hybridization [13] and studies using a more sensitive technique as polymerase chain reaction (PCR) have not been performed

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