Cervix carcinoma

Cervix

Anatomically the cervix consists of the external vaginal portio (ectocervix) and the endocervical canal. Ectocervix is covered by squamous epithelium and endocervix by columnar epithelium, the point where they meet is called squamocolumnar junction. The position of the junction is variable and changes with age and hormonal influence, in general the junction moves upward (squamous metaplasia)

Premalignant and malignant Neoplasms of the Cervix
High-risk HPVs are by far the most important factor in the development of cervical cancer. HPV-16 accounts for 60% of cervical cases and HPV-18 accounts for 10% cases, other HPV types contribute to less than 5% of cases individually. HPVs infect immature basal cells of the squamous epithelium in areas of epithelial breaks or immature metaplastic squamous cells present at the squamocolumnar junction. HPVs cannot infect the mature superficial squamous cells that cover the ectocervix, vagina or vulva. Establishment of HPV infection in these sites requires damage to surface  epithelium. Although HPV infects immature squamous cells, viral replication occurs in maturing squamous cells. The ability of HPV to act as a carcinogen depends on the viral proteins E6 and E7, which interfere with the activity of tumor suppressor proteins that regulate cell growth and survival. Normally the more mature cells are arrested in the G1 phase of the cell cycle, but they continue to actively progress through the cell cycle when infected with HPV, which uses the host cell DNA synthesis machinery to replicate its own genome.

• Viral E7 protein binds to the active form of RB and promotes its degradation via the proteasome pathway and also binds and inhibits p21 and p27, two important cyclin-dependent kinase inhibitors.
• Viral E6 proteins binds to tumor suppressor protein p53 and promotes its degradation. E6 also up-regulates the expression of telomerase.

Cervical carcinoma

The average age of patients with invasive cervical carcinoma is 45 years. Squamous cell carcinomas is the most common subtype accounting for 80% of cases. Adenocarcnoma accounts for 15% and adenosquamous and neuroendocrine carcinomas for 5%. 

Early invasive cancers may be treated by cervical cone excision alone, most invasive cancers are managed by hysterectomy with lymph node dissection and for advanced lesions radiation and chemotherapy. Most patients with advanced cervical cancer die of the consequences of local tumor invasion rather than distant metastatases.