**Abstract**

The fact that the human body is composed of cells was demonstrated by Dr. Hooke in 1665, and modern cytology was initiated by Dr. Papanicolaou in 1928. In 1943, Papanicolaou published "Diagnosis of Uterine Cancer by Vaginal Cytology," which is the basis of current cytodiagnostics. There are several types of materials used in cytological diagnosis, each with different methods of specimen preparation and determination. The advantages of some specimen collection methods are that they are less invasive to the body and provide quick determination results. However, correct results cannot be obtained unless the specimen is prepared correctly. In recent years, various methods have been developed with the advancement of imaging tests, the spread of genetic testing, and the spread of artificial intelligence (AI). Liquid-based cytology (LBC) has become widespread, especially in gynecology. It has also become possible to test for human papillomavirus (HPV), which is closely related to cervical cancer, using the same materials. An automated screening system based on a database of morphological characteristics of atypical/tumor cells has also been developed.

**Keywords:** Papanicolaou's classification, genetic testing, automated screening system, cytology, cervical cancer

### **1. Introduction**

Cytodiagnostics began in 1928 when modern cytology was commenced by Dr. Papanicolaou and was initially recognized for its usefulness as a diagnostic method for cervical cancer (see **Figure 1**) [1]. The examination of smears by Dr. Papanicolaou is one of the most important historical achievements in screening methods for the prevention of disease and cancer. It has been used as a screening test for uterine cancer since 1950. The test is straightforward and practical from a technical perspective and utilizes the simple scientific observation that malignant cells have abnormal nuclear morphology that can be distinguished from benign cells [2–4]. The International Academy of Gynecological Cytology (IAC), which was founded in 1957 and originated from the Japan Gynecological Cytology Discussion Group, was established in Japan in response to the International Academy of Gynecological Cytology (IAGC).

The Japanese Society of Clinical Cytology is a professional society that promotes academic research in clinical cytology and cytodiagnostics and the application of its results to practical clinical practice. Its origins date back to 1961.

Later, in line with advances in other fields of science, the IAC was renamed the International Academy of Cytology in 1961. In 1962, it was joined in Japan with the

#### **Figure 1.**

*Gynecological cytology by Dr. Papanicolaou. (a) Normal. (b) Inflammation. (c) Carcinoma. (a) a moderate number of inflammatory cells are seen in the background, and superficial-to-medium squamous epithelium is present. The patient is presumed to be an adult female. (b) A strong inflammatory background is present. (c) The cells differ in enlargement from (a) and (b), but have nuclei that are large and show shape irregularities. Quoted from reference [1], partially modified. George N. Papanicolaou. M.D, New Cancer Diagnosis,The Third Race Betterment Conference, Battle Greek. Michigan. January 2-6. 1928. And published in the proceedings of the Conference the same year.*

Tokyo Cytodiagnosis Study Group and others to be known as the Japanese Society of Clinical Cytology.

Since the early 2000s, the academic content of this society has covered numerous fields, including gynecology, surgery, internal medicine, pathology, dentistry, and especially cancer diagnosis. Notably, it is valuable as a means of cancer screening and is used for cervical, uterine, lung, and breast cancer screening. Among these, with its long history, cervical cancer screening has achieved significant results for reducing disease mortality. The Papanicolaou classification was used as a criterion (see **Table 1**). Cells are classified according to their morphological changes from benign (normal or near-normal cells) to malignant (cancerous cells). The Papanicolaou classification, which has five levels from Class I (no abnormality) to Class V (malignant), has been widely used in gynecological cytology because it is easy to compare with histological diagnosis and is common and convenient for other organs.


#### **Table 1.**

*Papanicolaou's classification from the Japanese Society of Clinical Cytology based on gynecology.*

#### *Cytological Evaluation DOI: http://dx.doi.org/10.5772/intechopen.109886*

Papanicolaou classifications I–V were established in cytology in Japan as the main classification method. Together with the Japanese grouping of the gastrointestinal tract, it supports an easy understanding of the stages of cancer. This classification was believed to be universal and unchanging, and thus, it was perplexing that "overseas, papers written using the Papanicolaou classification are not accepted." Twenty years ago, the Washington Post reported on the low rate of positive cytological diagnoses in the USA using the Papanicolaou classification, and this led to the establishment of the Bethesda system (see **Table 2**) [5–11].

Therefore, why the positive diagnosis rate was so low with the Papanicolaou classification became a question. Various theories exist, including that the specimens were of poor quality, there was an insufficient number of cells smeared, and fixation or staining was not performed properly. Therefore, emphasis was placed on whether enough cells had been collected, whether fixation was adequate, and whether the specimens had been prepared appropriately.

Cytology results are ultimately a judgment based on the individual cytological image obtained. A proper judgment cannot be made if an insufficient amount of sample was collected, thus demonstrating that a necessary quantity must be obtained. This suggests that without proper sampling, accurate determination is not possible. The following section describes the types of collection material and critical points and precautions for specimen preparation. This is very important for a correct assessment.

It has been revised in various ways, and now, some 60 years later, current gynecological cytology is undergoing further changes. Liquefied cytology, which was introduced in Japan later than in Western countries, is becoming more widespread. It is now possible to perform human papillomavirus (HPV) testing on samples taken at the same time [12–15]. This is the time when the efforts for the early detection and treatment of cervical cancer are relevant in terms of cytological diagnosis tests. Furthermore, automatic screening has been initiated.

Cytological tests are now being actively considered not only for cell morphology diagnosis, but also for the introduction of new technologies. These include molecular cytological research on genetic mutations during tumorigenesis and abnormal expression of oncogenes, automated cell diagnosis, and telecytology as part of telemedicine.
