- A recent study estimates worldwide HPV prevalence in cervical carcinomas at 99.7 percent (Walboomers et al., 1999).

- Studies also suggest that persistence of HPV infection is related to the development of cancer (Wallin, et al. 1999; Burk, 1999).

- Besides HPV, other risk factors appear to include certain sexual activity patterns and smoking (Brinton, 1992; Biswas et al., 1997; Prokopczyk et al., 1997, Roteli-Martins et al., 1998; Wen et al., 1999).

- In some developing countries, there is concern among clinicians that cervical cancer develops differently from what is traditionally described in Western countries (for example, concern that cervical cancer may develop at younger ages and that dysplasia progresses more quickly to invasive disease) (Rogo et al., 1990).

- A study of Pap smear results from ob/gyn clinics in South Africa found that a significant proportion of cervical cancer cases occurred in women younger than age 40 (Lancaster et al., 1999). Whether these results would have been the same with a true population-based sample is unclear. Few studies have conclusively demonstrated regional differences in the age-specific risk of cervical cancer; in general, cervical cancer risk peaks around age 50, and severe dysplasia risk peaks around age 35 (Ponten et al., 1995).