for many decades the microscopic observation of biopsied samples has been the mainstay of screening/diagnostic processes of cervical cancer even though this technique suffers from intra-observational subjectivity

for many decades the microscopic observation of biopsied samples has been the mainstay of screening/diagnostic processes of cervical cancer even though this technique suffers from intra-observational subjectivity. despite numerous technical innovations that have been developed to detect cancer in their earliest stages of formation unfortunately the detection of many cancers at the microscopic level is often too late for successful intervention fong fortner et al. 1999 unlike many genitourinary infections cervical cancer is not usually associated with immediate symptoms such as itching burning or vaginal discharge mao hughes et al. 2003 the initial changes that may occur in some cervical cells are not cancerous. however these precancerous cells form dysplasia or sil within the epithelial or outer layer of cells. the majority of all mild dysplasias regress spontaneously within less than a year figure 2.14 a proportion of the hr hpv infections will however become persistent and if left untreated proceed to high-grade lesions and invasive cervical cancer. the long transit time from early cervical atypia to invasive cancer provides an opportunity to identify pre-cancerous at a stage where safe and affordable treatment is available making it appropriate disease for the application of screening principles. taken together diagnosis and prognosis of asymptomatic invasive disease is very poor but treatment of pre-invasive lesions is highly effective dewar hall et al. 1992 it is well established that no single screening method exists that is highly sensitive highly specific affordable and practical gheit vaccarella et al. 2009 the field of detection has been plagued by problems of over diagnosis inadequate specificity of individual markers cancer antigen-125 carcino embryonic antigen low compliance colonoscopy and a lack of analytical tools for discovering new detection methods. hence there is an obvious interest in identifying markers that could complement standard cyto/histopathologic evaluation to determine the presence of cancer cells in tissues. thus in cervical cancer screening biomarkers are needed that allow to identify persons at risk to develop cancer at a time point that still allows for a successful curative intervention before invasive cancer develops. in addition to screening markers biomarkers could be used for a risk assessment of detected lesions to stratify intermediate lesions to predict progression and to monitor recurrences after treatment. a very interesting field for biomarkers could be the assessment of cin1 and cin2 lesions. the initial event in cervical transformation is an infection with hr-hpv. the major hallmark of progression from hpv infected tissue to dysplastic lesions is the altered expression pattern of the hpv oncogenes duensing lee et al. 2000 duensing and münger 2001 duensing and münger 2002 biomarkers are subdivided on the basis of the most important cellular and viral changes from hpv infection to invasive cancer. p16ink4a: the p16 is a cell cycle regulatory protein which is the main target of hpv. p16 is an inhibitor of cdks 4 and 6 and functions in the progression from g1 to s phase of the cycle cell. in hpv infection with hr types p16 is over expressed klaes friedrich et al. 2001 the p16 protein can be detected in both histology specimens as well as in lbc sahebali depuydt et al. 2004 over-expression of p16 is correlated with hpv type 16 and 18 and can be detected in both squamous cell carcinoma and adenocarcinoma schorge lea et al. 2004 tringler gup et al. 2004 in biopsies of suspicious cervical lesions p16 is used to discriminate the low grade lesions with potential to progress to high-grade lesions klaes benner et al. 2002 passamonti gustinucci et al. 2010 sung kim et al. 2010 dna aneuploidy: earlier reports duensing and münger 2001 duensing and münger 2002 have shown that disturbances of the mitotic spindle apparatus are induced early by deregulated expression of hpv oncogenes resulting in non-diploid nuclei aneuploidy consequently aneuploidy is characteristic for hpv transformed lesions even at precancerous stages bollmann bollmann et al. 2001 bollmann méhes et al. 2003 melsheimer vinokurova et al. 2004 the studies have shown an association between aneuploidy and increasing dysplasia. hpv integration: it is believed that hpv dna is integrated by chance during the cellular repair processes of double strand breaks. as such hpv integration is an indicator of severe ongoing chromosomal instability and an advanced stage of the transformation process wentzensen vinokurova et al. 2004 the detection of hpv dna test alone is employed as a primary screening method to exhibit it as more sensitive than cytology among abundant clinical studies. since hpv testing is more sensitive than cervical cytology in detecting cin 2 and cin 3 women with concurrent negative test results pap and hpv test can be reassured that they have no risk of unidentified cin 2 cin 3 or cervical cancer castle solomon et al. 2005 walker wang et al. 2006 widschwendter et al. suggest that the serum hpv dna might be a useful additional marker for early detection of recurrence in cervical cancer widschwendter blassnig et al. 2003 several methods exist to detect the integration of hpv dna into the host genome. the main hpv testing methods that have well defined clinical applications at present are polymerase chain reaction pcr and hybrid capture ii hc2 real-time pcr and mrna testing are techniques of growing interest koliopoulos valasoulis et al. 2009 schiffman wentzensen et al. 2011 a simple approach is the real time pcr-based quantification of the e2 and e6/e7 gene ratio peitsaro johansson et al. 2002 e2 is frequently lost upon hpv integration and the theoretical ratio of 1:1 between the two genes is expected to be shifted towards e6/e7. dysplastic cells show increased cell cycling. therefore markers of cell proliferation might be a logical choice as biomarkers for cin. ki67: the increased proliferation of cervical epithelial cells induced by deregulated hpv oncogene expression is reflected by the activation of proliferation markers such as ki67 mib-1 this protein is strongly expressed in cin lesions but can also be found expressed in normal basal cells that retain proliferation capacity pirog baergen et al. 2002 goel mehrotra et al. 2005 myc: the cellular oncogene myc is frequently found amplified and over-expressed in cervical cancer. studies have shown myc activation at premalignant stages indicating that myc detection might be used to assess dysplastic lesions. golijow abba et al. 2001 cyclins: they are a large family of regulatory proteins with central functions in the coordination of the cell cycle. the expression of several cyclins has been analyzed in cervical cancer and pre-cancer. cyclin d1 was found to be over-expressed in low grade lesions induced by lr-hpv while it was absent in hr-hpv induced lesions southern and herrington 1998 other cyclins such as a b and e were found to be over-expressed in premalignant cervical lesions keating cviko et al. 2001 el-ghobashy shaaban et al. 2004 telomerase: telomerase expression is important to counteract the loss of sequences located at the outermost chromosome endings that naturally occurs during every cell division. the gene encoding the rna subunit of telomerase terc is located on chromosome 3q a region that is frequently amplified in cervical cancer and pre-cancer. since telomerase is necessary to maintain telomere length in proliferating cells it is found over-expressed in many human cancers. several groups have used a functional telomerase assay to evaluate telomerase activity on cervical smears jarboe thompson et al. 2004 ault allen et al. 2005 replication complex proteins: mcm5 and cdc6 belong to the dna pre-replication complex that is usually expressed in replicating but not in quiescent cells.