**1. Introduction**

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Squamous cell carcinoma, adenocarcinoma and adenosquamous carcinoma comprise the most common cancers of the uterine cervix. Cervical cancer is one of the common cancers in women, especially in certain parts of the world, as Sub-Saharan Africa, Central America, South Central Asia and Melanesia [1]. In several countries the incidence of cervical cancer was reduced after the introduction of effective screening methods and prevention programs, initially based on the Papanicolaou smear (Pap test), and it is expected to diminish much further with the introduction of vaccination against human papilloma virus (HPV) [2-4].

In recent years papilloma virus has been linked to these cancers through a significant amount of scientific data, derived from epidemiologic, clinical, experimental and molecular studies [5-10]. A. large number of scientific reports during the last three decades led to an explosion of information regarding the role of HPV in lower genital tract carcinogenesis, thus paving the way for the introduction of effective vaccines against the virus, expected to diminish the incidence of both HPV-related carcinomas and precursor lesions in forthcoming years [2,3,5]. This has affected in several ways the histopathologic diagnostic approach to cervical carcino‐ mas and their precursor lesions, including the classification and terminology of the latter. Although several important questions remain, we are now able to examine HPV-related morphologic alterations from a different perspective that encompasses parts -although limited- of this new information, in an effort to achieve more efficient and precise recognition of precancerous lesions.

In the field of cervical squamous precursor lesions the basic concept underlying the Cervical Intraepithelial Neoplasia (CIN) terminology, which refers to a single disease spectrum, has

© 2013 Kostopoulou and Koukoulis; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

been questioned and gradually replaced by various approaches trying to face the whole group of HPV-related histopathologic abnormalities. In the field of glandular precursor lesions adenocarcinoma in situ is considered the precursor to most invasive cervical adenocarcinomas, while the concept of glandular "dysplasia" is being evaluated [11-15].

terminology became the most widely used for the next decades and is currently in use in many

Ancillary Techniques in the Histopathologic Diagnosis of Squamous and Glandular Intraepithelial Lesions…

http://dx.doi.org/10.5772/55897

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The recognition of the important role[s] of human papillomavirus in cervical carcinogenesis gradually led to different approaches, concerning the whole group of HPV-related lesions and their classification, based on more recent biologic and molecular data [11,13,30,31]. Among them the distinction between two basic biological entities was included: specifically, between a productive viral infection and an intraepithelial neoplastic process. Several questions remain to be answered; however, on a practical level, patient management remains an important basis

In the last decades a binary system of classification based on The Bethesda System [TBS] has been mainly in use by cytopathologists; however, several histopathology laboratories world‐ wide have also adopted similar terminology. A binary system is more consistent with the current knowledge concerning HPV-related disease and is considered to form a basis for improved communication between gynaecologists and pathologists [31]. Moreover, the intermediate group (IN2) has not been shown to comprise a reproducible diagnostic category

The terms squamous intraepithelial lesion (SIL) of the uterine cervix or cervical intraepithelial neoplasia (CIN) encompass a group of alterations of squamous epithelium that usually occur

Abnormal proliferation and maturation of squamous cells and nuclear atypia, including enlargement, pleomorphism, irregular nuclear borders, and change in chromatin texture, are the characteristics of these intraepithelial lesions. In one group of lesions the observed cellular alterations reflect mainly viral cytopathic effect, corresponding to koilocytic atypia. This is characterized by an abnormal appearing nucleus surrounded by an irregularly shaped cytoplasmic halo with a sharp edge. In these lesions atypia is more conspicuous in the maturing squamous cells, with mild alterations of the basal-parabasal cell morphology. In other groups of lesions cellular atypia is conspicuous in all cell layers: both middle/upper and lower

Low-grade squamous intraepithelial lesions (LSILs) exhibit differences in density, size and staining of the maturing squamous cells, often accompanied by binucleated cells, cytoplasmic halos, and/or changes in epithelial thickness (Fig.1a)[14]. High-grade squamous intraepithelial lesions (HSILs) exhibit conspicuous nuclear atypia in all epithelial layers, with nuclear crowding, high nuclear:cytoplasmic ratio, loss of normal polarity, irregular nuclear mem‐ branes, and increased mitoses, which can be atypical [32]. In these lesions koilocytosis may be identified or not. There is significant basal/parabasal atypia, with little or no cytoplasmic maturation in the middle-upper layers of the epithelium, and mitotic activity extends to these

The differential diagnosis includes mainly: (a) reactive epithelial changes, (b) immature metaplastic changes, and (c) postmenopausal/atrophic epithelia, which may all mimic

laboratories worldwide.

among pathologists.

epithelial layers (Fig.1)

epithelial layers (Fig.1c).

that influences and often guides choices of terminology.

**2.1. Precursor lesions of squamous cell carcinoma**

in or close to the transformation zone and are related to HPV.

Morphology represents a gold standard for lesion diagnosis, since histologic and/or cytologic examination allows in most cases the recognition of viral cytopathic effects and precancerous epithelial alterations; however it can be hampered by inter- and intra-observer variability. In this context, several biomarkers have been investigated for their potential utility in assisting the histopathologic classification of preinvasive lesions and facilitating their distinction from non-HPV induced alterations [16-21]. Human papillomavirus-related intracellular interac‐ tions formed the basis for the identification of markers that may assist in this distinction, including cellular proteins targeted directly by viral oncoproteins, and markers related to the cell cycle, which is disturbed by multiple actions of the virus. Additionally, it is expected that the correlation of slight cellular alterations with new sensitive methods of HPV-detection might lead to the identification of different groups of lesions of clinical significance, as well as to the correct application of current morphologic criteria [21-23].

The application of immunohistochemistry and in situ hybridization techniques in the histo‐ pathologic diagnosis of cervical intraepithelial alterations of both squamous and glandular epithelium will be presented in this chapter. The immunohistochemical markers that are currently in use in several laboratories worldwide, as well as some new promising biomarkers will be included. Scientific background for each of these markers and special indications for their application will be summarized. A synoptic review of the pertinent literature will be presented, in an effort to summarize the existing data and the remaining questions at both the practical and the theoretical level.
