Development of cervical cancer caused by HPV16

Initial infection

Delivery of infective virions to the host's basal epithelial layer.

Viral persistence

Maintenance replication with concomitant transformation of the infected cells. Most cervical HPV infections are cleared or suppressed to undetectable levels by cell-mediated immunity within 1-2 years of exposure.

Cervical

intraepithelial

neoplasia

(CIN) MeSH

A malignancy arising in uterine cervical epithelium and confined thereto, representing a continuum of histological changes ranging from well-differentiated CIN 1 (formerly, mild dysplasia) to severe dysplasia/carcinoma in situ, CIN 3. The lesion arises at the squamocolumnar cell junction at the transformation zone of the endocervical canal, with a variable tendency to develop invasive epidermoid carcinoma, a tendency that is enhanced by concomitant human papillomaviral infection. (Segen, Dictionary of Modern Medicine, 1992)

Cervical

intraepithelial

neoplasia

grade 1

(CIN1) MeSH

Also, uterine cervical dysplasia. CIN1 is an insensitive hystopathological manifestation of HPV infection. For any given type of carcinogenic HPV, diagnosing CIN1 does not predict higher risk of progression to CIN3 than does negative biopsy. Patients confirmed with the infection (by detection and genotyping of the virus DNA), which had manifested in CIN1 (detected by Pap test and other cytology-based methods) are usually diagnosed only as having abnormalities and are not targeted for treatment. Instead, they might be scheduled for a follow-up examination without falsely informed as being at risk of cancer.

Precancer

The time between infection and appearance of the first microscopic evidence of precancer can be quite short, often within 5 years. The average age of diagnosis of precancer varies from 25 to 35 years and depends on the average age at the first intercourse and on the intensity of screening. In case of highly carcinogenic HPV16 precancer diagnosis can reach as high as 40% of all detected infections.

Cervical

intraepithelial

neoplasia

grade 2

(CIN2)

CIN2 is heterogeneous and sometimes is produced by non-carcinogenic types of HPV. CIN2 should be treated, often simple outpatient procedures (for example, cryotherapy) with subsequent follow-up exams are sufficient.

Cervical

intraepithelial

neoplasia

grade 3

(CIN3) MeSH

Carcinoma in situ. A lesion with cytological characteristics associated with invasive carcinoma but the tumor cells are confined to the epithelium of origin, without invasion of the basement membrane. In case of CIN3 undifferentiated cells with fixed genetic abnormalities have replaced almost the full thickness of the cervical epithelium. Without immediate treatment CIN3 progresses to invasive cancer.

Invasive cancer

Also called infiltrating cancer. Cancer that has spread beyond the layer of tissue in which it developed and is growing into surrounding, healthy tissues (Dictionary of cancer terms, NCI).

The peak risk of invasive cervical cancer occurs at 35-55 years of age. The invasive cervical cancer is graded from grade I to IV. Treatment of grade I requires surgery of different degrees of invasiveness. In many cases patient's fertility can be preserved. Higher grades might require the surgery to be accompanied with radio- or chemotherapy.