Human papillomavirus infections in the pathogenesis of oesophageal cancer in the high risk area of China
During 1990-1992 our Chinese collaborators in Zhengzhou, China collected a series of more than 2000 oesophageal specimens derived from more than 700 patients suffering from a variety of oesophageal squamous cell lesions, with pertinent clinical data available. These specimens have been derived from both the high-incidence area for oesophageal cancer in Linxian county of Henan province in China as well as from the low-incidence areas in China and Finland. Using multiple histopathological and deoxyribonucleic acid (DNA) detecting techniques routinely used in our papillomavirus research laboratories in Kuopio (Finland) and Heidelberg (Germany), such as light microscopy, electron microscopy, immunohistochemistry, DNA in situ hybridization, Southern blot hybridization, dot blot hybridization, polymerase chain reaction, single strand conformation polymorphism (SSCP), as well as viral isolation, cloning and DNA sequencing techniques, a systematic evaluation of the associations of infectious agents (human papillomavirus (HPV) in particular) with oesophageal cancer (EC) is being conducted as a concerted action. Meanwhile, the prognostic factors for EC are being analyzed in Siena (Italy) by using immunohistochemical staining for a variety of tumour market proteins and by a variety of histoquantitative methods.