Moberg M et al. (2005) High viral loads of human papillomavirus predict risk of invasive cervical carcinoma. Br J Cancer 92: 891–894

Previous studies have suggested that a high human papillomavirus (HPV) load in cervical smears with normal cytology may be connected with the risk of developing dysplasia and carcinoma in situ. However, whether there is an association between high viral load in cervical smears and invasive cervical cancer is not yet known. Therefore, Moberg and colleagues from Sweden investigated smears from 62 cases diagnosed with invasive squamous cell carcinoma of the cervix, together with 501 control subjects.

The results showed that 45% of the cases and 6% of controls tested positive for HPV-16, with the odds ratio increasing with viral load, reaching a maximum of 51 (P = 0.0001). HPV-31 was found in 8% of cases and 4% of controls, and HPV-18 plus HPV-45 was detected in 13% of cases and 6% of controls. The odds ratio for HPV-31 and HPV-18 plus HPV-45 was significant only for the highest viral load percentiles.

From these results, the authors conclude that an increasing viral load of HPV-16 in cervical smears increases the risk of developing invasive cervical cancer later on in life, and therefore viral load can be used as a risk marker for invasive cancer. However, further studies are needed to investigate the physical state and load of the virus, in order to determine the importance of these factors in the development of cervical cancer.