Vaccines against human papillomaviruses--a major breakthrough in cancer prevention

Prophylactic vaccines against cancers of non-infectious origin: a dream or a real possibility?

The dramatic progress in tumour biology and immunology in the past several years has opened new avenues for the treatment and prevention of cancer. One of the great contributions of the immunotherapeutic approaches is an increasing understanding of the immunology of cancer, which is, gradually creating conditions for the development of prophylactic anti-cancer vaccines. Efficient vaccines have been developed and employed for the prophylaxis of two frequent cancers of viral origin, namely cervical cancer and liver cancer. The new knowledge on the interactions between the immune system and the malignant tumors seems to provide means for the development of prophylactic vaccines against cancers developing due to the mutations in the proto-oncogenes converting their products into oncoproteins. According to the present estimates, these cancers form a great majority of human malignancies. Recent evidence has indicated that the immune system recognizes such mutated proteins, and that the development of cancer is due to the failure of the immune system to eliminate neoplastic cells. Followingly, it can be expected that inducing immunity against the mutated epitopes will increase the capacity of the body to deal with the initiated precancerous cells. In the present paper this hypothesis is primarily discussed in the relationship with colorectal cancer (CRC), which seems to be a well-fitting candidate for prophylactic vaccination. CRC is the third most frequent malignancy and the fourth most common cause of cancer mortality. Mutations of two proto-oncogenes, namely RAS and RAF, are involved in the majority of CRC cases and, in addition, they are shared with other human malignancies. Therefore, the strategy to be used for prophylaxis of CRC is discussed together with several other frequent human cancers, namely lung cancer, pancreatic duct cancer and melanoma. The prophylactic vaccines proposed are aimed at the reduction of the incidence of these and, to a lesser extent, some other cancers.

Knowledge and awareness of female sex workers towards human papillomavirus infection in Turkey

OBJECTIVE

The aim of this study was to determine the knowledge and awareness of female sex workers (FSWs) about human papillomavirus (HPV) infection in Turkey.

METHODS

239 brothel-based FSWs were recruited for an interview. A questionnaire was completed by face to face interview. The demographic features, the level of knowledge, and awareness about HPV infection of the participants were recorded.

RESULTS

A total of 152 (63.6%) were over 30 years of age, and 210 (87.9%) completed primary education. 122 FSWs (50.9%) were using condom, and about one third had high frequency of sexual contacts. Knowledge scores were < OR =4 in 181 (75.7%) FSWs. Low education and higher age group were not significant predictors of low knowledge scores. Low education was not an independent risk factor for awareness but higher age group participants were significantly less aware of risks associated with HPV infection (p = 0.019) although overall score was very poor (0.60 +/- 0.68).

CONCLUSIONS

The knowledge and awareness about HPV infection and its possible consequences (cervical cancer) as well as the utility of screening methods among FSWs in Turkey are extremely poor. HPV-focused educational programmes for targeted populations, e.g. FSWs and young adults prior to their sexual activity, should be launched urgently to increase awareness of the risks associated with HPV infection and thus reducing the incidence of cervical cancer in Turkey in the future.

Human papilloma virus vaccination: perceptions of young Korean women

AIM

This paper is a report of a descriptive study of young Korean women's perceptions of use of the human papilloma virus vaccine.

BACKGROUND

In Korea, cervical cancer is one of the leading cancers in women, and the rate of human papilloma virus infection is increasing. A national media campaign has recently begun to promote human papilloma virus vaccination. However, research addressing the acceptability of this vaccine to women in Korea has been limited.

METHOD

Twenty-five Korean women, 21-30 years of age, participated in seven focus groups. The data were collected in 2007.

FINDINGS

Participants were concerned about the potential harmful effects of the human papilloma virus vaccine, a possible increase in unsafe sexual behaviours, and the high cost of the vaccine, which is not covered by health insurance. They suggested group vaccination at-cost or free of charge. They discussed ambivalence about the vaccination, the need for more information about the vaccine, and questions about its effectiveness. Most preferred to wait until more people have been vaccinated.

CONCLUSION

There is a need for more aggressive dissemination of information about the safety and efficacy of the human papilloma virus vaccine. More reasonable cost, insurance coverage, or free vaccination using a group approach might increase young Korean women's acceptance and use of the human papilloma virus vaccine.

Identification of vaccine human papillomavirus genotypes in squamous intraepithelial lesions (CIN2-3)

OBJECTIVE

To identify the prevalence of human papillomavirus vaccine genotypes and non-vaccine genotypes implicated in the appearance of cervical intraepithelial neoplasia (CIN2-3).

METHODS

Prospective study of 519 women with abnormal cytology. All the women underwent a second Papanicolaou test, cervicovaginal sampling for type-specific HPV detection and colposcopy, and women with abnormal colposcopy results were referred to biopsy. Pearson's chi-square test was used for statistical analysis.

RESULTS

HPV was detected in 340 patients (65.5%), and in 125 (24%) more than one HPV genotype was present. We selected 206 patients with CIN2 or CIN3 confirmed by biopsy. In 88 (42.7%) of these patients, HPV types 16 and 18 were detected, but only 58 (28.2%) without co-infection by other high-risk or probable high-risk HPV types. In 115 (55.8%) women diagnosed with CIN2 or CIN3 high-risk or probable high-risk HPV types other than 16 or 18 were found. High-risk and/or probable high-risk HPV genotypes not included in the vaccine were isolated in this study more frequently than 16 or 18, and this difference was statistically significant (p=0.047). Of the 206 women diagnosed with CIN2 or CIN3, 19 tested negative for HPV and 14 tested positive for low-risk HPV types.

CONCLUSION

Only 28.2% of women with CIN2 or CIN3 confirmed by biopsy were infected exclusively by HPV type 16 or 18, a finding that places in doubt the degree of protection afforded by HPV vaccination.