First, all sera were screened on the presence of Ig G antibody against HPV 16 capsids containing L1 proteins.The positive sera were further tested on the presence of Ig G antibody against HPV 16 E7 peptides.
Sera from patients with gastric carcinoma were considered as HPV-negative cancer control sera.
For the HPV-negative control group without cancer, serum specimens were selected from the serum bank in the Slotervaart (SL) hospital.
Presence of HPV DNA in carcinomas of the penis is observed in a proportion of the specimens analysed (Grussendorf-Cronen, 1997; Tornesello et al, 1997; Dianzani et al, 1998; Levi et al, 1998; Poblet et al, 1999; Dillner et al, 2000; Rubin et al, 2001).
Some serological studies relative to HPV infection in individuals with penile carcinoma were carried out in relatively small groups of patients (Wideroff et al, 1996b; Strickler et al, 1998; Carter et al, 2001).
A retrospective seroepidemiologic study was performed to examine the association between human papillomaviruses (HPV) 16 infection and carcinomas of the oropharynx, the oesophagus, penis and vagina.
Sera were selected from the serum bank from the Antoni van Leeuwenhoek Hospital (Netherlands Cancer Institute) and the Slotervaart Hospital in Amsterdam, the Netherlands.
The specimens were stored at −20°C and transported on dry ice to the Karolinska Institute, where the assays were performed by CM Korse and JCGM Buning-Kager.
The pathological diagnosis was made at the Department of Pathology of the Av L hospital and the SL hospital, respectively, using standard methods, and coded according to international standards (WHO, 1979).
Baculovirus-expressed HPV16 capsids containing both the L1 proteins were diluted in cold phosphate-buffered solution (PBS) to 1 μg ml, coated overnight at 4°C onto microtiter plates and subsequently blocked with 10% horse serum in PBS (HS-PBS).
Sera were diluted 1 : 30 with HS-PBS and added to the plates for 2 h at room temperature (RT).
Presence of HPV 16 specific antibody was assessed using HPV 16 L1 capsids.