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Glossary
| Term | Definition |
| Acetowhitening | During colposcopy or visual inspection, 3-5% acetic acid is applied to the cervix, which is then visualised using a white light. The white light reflects off enlarged nuclei in cells, showing up abnormal or inflamed tissue. This technique is used to detect cervical abnormalities. |
| Adenocarcinoma | A carcinoma arising from glandular cells. Adenocarcinomas tend to occur in the endocervical canal while squamous cell carcinomas appear more commonly on the ectocervix. Adenocarcinomas also tend to occur deeper in the basal layer of cells underlying the epithelium. This means they can be harder to detect, and are therefore often missed by conventional screening methods or by follow-up colposcopy after screening has indicated atypical glandular cells or adenocarcinoma in situ. |
| Age-standardised | Where incidence or mortality statistics are age-standardised, they have been adjusted to take into account the age distribution of the population being studied (ie, the number of old or young people). Rates are age-standardised to ensure that differences in rates over time or between geographical areas do not simply reflect variations in the age structure of the populations. |
| Antibody | An immunoglobulin protein produced by plasma cells, which are an important component of the body’s defence against an invading pathogen (e.g., virus, bacterium). The antibody recognizes specific foreign antigens and tags them for elimination or destroys them directly. |
| Antigen / Antigenic peptide | A substance that induces an immune response when introduced into the body. A natural antigen can be a fragment of a virus, bacterium or foreign protein that stimulates the production of cytotoxic T-lymphocytes and antibodies. Alternatively, vaccines contain antigens that are artificially introduced into the body in order to induce this response. The antigen may be presented on the outer surface of an infected cell where it is recognised by cells of the immune system. |
| ASC-US | Atypical squamous cells of undetermined significance, as identified by a cervical screening test. This finding can refer to any lesion that cannot be classified by the cytologist, but most often represents a low risk of progression to invasive cervical cancer. |
| Base pairs | Complementary pairs of DNA bases. The number of base pairs is a measurement of the DNA content of an organism, known as its genome. The human genome contains approximately 3 billion base pairs. The HPV genome contains approximately 8000 base pairs. |
| Biopsy | The surgical removal of a small tissue sample (around 4 x 3 x 2 mm for a cervical biopsy) to allow accurate diagnosis of a suspected lesion. |
| Brachytherapy | A localised form of radiotherapy. Radioactive seeds or sources are placed in or near the tumour, giving a high radiation dose to the tumour while reducing the radiation exposure in the surrounding healthy tissues. |
| Capsid | The outer shell of a virus. The HPV capsid is made up of two structural proteins, L1 and L2. L1 proteins form repeating pentamers. These are supported by L2 proteins to give the virus its spherical structure. |
| Cell-mediated | The cell-mediated immune response is the branch of the adaptive immune system that does not involve antibodies. This response involves the production of antigen-specific cytotoxic T-lymphocytes (CTLs) and the release of various cytokines in response to an antigen. CTLs, when mobilised, are able to eliminate cells displaying foreign antigens on their surface, such as those infected by a virus. Helper T-lymphocytes can also stimulate and support a humoral, or antibody-mediated immune response, particularly in response to vaccination. |
| Cervical screening | Cervical screening is the process of collecting cells from a woman’s cervix. Cells are collected by a healthcare practitioner and subsequently analysed for cervical abnormalities by a histopathologist. Any abnormalities may be indicative of pre-cancerous development or invasive cervical cancer. The process works best when screening is repeated every 1-3 years. |
| Chemotherapy | The use of drugs to stop the growth of cancer cells, either by killing them or by stopping them from growing and dividing. |
| CIN | Cervical Intraepithelial Neoplasia is a histological finding indicative of pre-cancerous changes in the cervix. CIN I represents mild dysplasia, CIN II moderate dysplasia and CIN III severe dysplasia or carcinoma in situ. CIN II is considered to be a high-grade precursor lesion in some countries (and grouped with CIN III) but grouped with CIN I in other countries. |
| CIS | Carcinoma in situ. An older term now encompassed by CIN III. |
| Colposcope | A bright light and magnifying lens used to see the cervix (and anogenital lesions) during a colposcopy. |
| Colposcopy | A diagnostic procedure in which a trained coploscopist visually examines a woman’s cervix using acetic acid or sometimes Lugol’s iodine for evidence of cellular abnormalities. |
| Co-morbid | A co-morbid condition is a clinical condition that exists alongside the disease that is being studied. Interactions between the two conditions may cause complications, for example co-morbid conditions affecting the integrity of the immune system may increase the risk of an HPV infection becoming persistent. |
| Cryotherapy | The removal of lesions by freezing. It involves the use of liquid cryogen, often nitrogen gas under pressure, applied with a disc to the surface of the cervix. It is as effective as LEEP for treatment of CIN if a double freeze is used. |
| Cytokines | Cytokines are a large group of intercellular messenger proteins, such as interleukins and interferons, that regulate the activity of cells of the immune system. |
| Cytotoxic | Cell-killing. In the context of chemotherapy, cytotoxic treatments are aimed at destroying cancerous cells. In the context of immunology, cytotoxic T-lymphocytes (CTLs) aid in the destruction of infected cells. For example, CTLs are involved in coating the target cell with antibodies specific for virally coded surface antigens, a process that can help improve the specificity of the natural killer (NK) cell response. |
| Dysplasia / dysplasias | Abnormal cellular morphology seen in tissue samples, including changes in cell size, shape and organisation. Mild cervical dysplasia is classed as cervical intraepithelial dysplasia (CIN) I, moderate dysplasia is classed as CIN II and severe dysplasia CIN III. |
| Dysplastic | Showing dysplasia. Dysplastic tissue can contain cells with abnormalities in cell size, shape and organisation. |
| Envelope | A protective outer shell, consisting of fat and protein molecules, that surrounds some viruses. HPV is a non-enveloped virus. |
| Epidemiology / epidemiological | The study of the patterns, causes and control of disease in groups of people. This branch of medical science deals with the incidence and distribution of disease at a population level. |
| Epithelial cells/epithelium | Tissue composed of single or multiple layers of cells, which forms the internal or external lining of many organs. The epithelium may be a single layer of cells or multilayered (stratified); both types of epithelium are found in the cervix. |
| False negative | A test result falsely reporting a normal outcome. In the context of cervical cancer, a false negative cervical screening test result is one where abnormal cells were present on the cervix, but the slide was classified as normal. The most common cause of false negative results is a failure to collect abnormal cells on the slide, particularly when the abnormal cells lie deep within the cervix or in the basal layers of the epithelium. This is particularly common with adenocarcinoma and its precursors. |
| False positive | A test result reporting an abnormal outcome when the disease is definitely not present. In the context of cervical cancer, a false positive cervical screening test result is one in which there are no abnormal cells on the cervix, but the slide is classified as abnormal. Candida infection can make the cells appear slightly abnormal and result in a borderline screening test result, as can recent sexual intercourse. |
| G1 phase | The cell cycle phase between M phase (mitosis or cell division) and S phase (DNA synthesis). In most cells, the majority of cellular growth occurs during G1 phase. |
| Genome | The complete genetic composition of an organism. The HPV genome consists of a single, circular, double-stranded DNA molecule that is 8000 base pairs long. |
| Homology | The degree of relatedness between two DNA sequences. |
| HPV | Human papillomavirus. |
| HSIL | High-grade squamous intraepithelial lesion. A cytological finding from a cervical smear test showing the presence of cells with moderate to severe dysplasia. |
| Humoral | The humoral immune response is the branch of the adaptive immune system that involves antibodies. This response involves the clonal expansion of antigen-specific B-lymphocytes, which produce antibodies to destroy foreign molecules |
| Hysterectomy | An operation to remove the uterus and usually also the cervix. If a cervical cancer has spread beyond the cervix and uterus, a hysterectomy may also involve the removal of surrounding tissues and organs (radical hysterectomy). |
| IgG (antibody) | Immunoglobulin G is the most common immunoglobulin found in the blood stream, and the type of antibody produced late in the immune response and in a booster response. They identify and neutralize foreign objects like viruses and bacteria. Each antibody recognizes a specific antigen unique to its target. |
| Incidence/incidences | The number of new cases of a disease arising in a given period in a specified population. |
| Keratinisation | Deposition of keratin on epidermal cells to form a tough barrier. Sometimes known as cornification or hornification, this is a process normally found on the palms of the hands or soles of the feet. |
| Koilocytosis | A condition of certain cells characterized by perinuclear vacuolation, indicative of HPV infection and synonymous with CIN I or LSIL. Koilocytes display perinuclear vacuolation, i.e., a vacuole surrounding the nucleus. |
| LEEP | Loop electrosurgical excision procedure. Involves the excision of the transformation zone of the cervix , and a small part of the endocervical canal. |
| Lesions | A general term to describe an area of abnormal tissue. Cervical lesions caused by HPV infection are often characterised by cells with enlarged nuclei, irregular nuclear membranes, granular chromatin and a high nuclear to cytoplasmic ratio. |
| Liquid-based cytology | A cervical screening technique that involves placing the collected cervical cells in a liquid preservative that is designed for testing for cervical cancer. With liquid-based cytology the head of the spatula used to collect cells is agitated or stored in preservative fluid. |
| Low-risk | Low-risk HPV types have little or no demonstrated link to cervical cancer. Low-risk HPV types can cause the growth of abnormal cells or warts on the hands, feet or anogenital areas, but generally only the high-risk, oncogenic HPV types can lead to cancer. |
| LSIL | Low-grade squamous intraepithelial lesion. A cytological finding from a cervical smear test showing HPV infection. Equivalent to the histological finding CIN I, LSIL may also include koilocytosis. |
| Lymphangiogram | A technique used to determine if a cancer has spread to the lymph nodes. A dye is injected into the lymph vessels of the feet, and X-rays are taken as the dye spreads through the lymph system. Blockages may indicate that a cancer has spread. |
| Lymphocytes | White blood cells that form a key component of the adaptive and innate immune systems. T-lymphocytes direct the cell-mediated immune response, while B-lymphocytes direct the antibody-mediated immune response, also known as the humoral response. |
| Menopause | The time at which a woman’s menstrual cycle ceases and she can no longer conceive naturally. The menopause typically occurs when a woman is in her 50s. |
| Metaplastic/metaplasia | Referring to an area where cells of one type are being replaced by cells of a different type, in a process known as transformation. |
| Metastasized | A cancer that has metastasized has spread from the primary tumour site to other organs and tissues of the body. |
| Mortality | The number of deaths due to a disease occurring in a given period in a specified population. |
| Neoplastic | A growth of abnormal cells that may reproduce faster than normal, and which may create a mass that can be benign or cancerous. |
| Odds ratio | The probability of the occurrence of a disease in a risk group divided by the odds for the disease in a control group. A ratio of greater than 1.0 means there is a higher risk associated with the event or activity. |
| Oncogenesis | The transformation of cells from healthy to cancerous. |
| Oncogenic | Cancer causing. Oncogenic HPV types are found in 99.7% of cervical cancers, and are also implicated in the development of some anal, penile, vulval, vaginal, oropharyngeal and oesophageal cancers. |
| Oncogenic transformation | The changing of a cell from healthy to malignant (cancerous). |
| Pap | ‘Pap smear’ testing detects the presence of abnormal cervical cells and forms the basis of many cervical cancer screening programmes around the world. It is named after the pathologist Dr George Papanicolaou who developed the technique. |
| Parity | The number of live births. |
| Persistent | A persistent infection is not cleared by the host immune system. In the case of HPV, a persistent infection is usually defined as being present on two or more successive examinations at least six-months apart. Persistent oncogenic HPV infection of the cervix can lead to cervical cancer. |
| Phylogenetics | The evolutionary history of an organism or virus, as determined by comparison of DNA sequences between similar specimens. The phylogenetics of HPV are relatively well understood and its small, highly stable DNA-based genome has not changed significantly over the past 200,000 years. One base pair changes approximately every 10,000 years. |
| Phagocytosis | The process of engulfing or ingestion of foreign bodies, such as bacteria or viruses, by specialist immune cells. |
| Prevalence | The number of persons in a defined population who have been diagnosed with a disease, and who are still suffering from the disease at a given point in time. The data presented here describe the one-year prevalence of cervical cancer; the number of women who have been diagnosed with the disease and remain alive after one year. |
| Primary prevention | Protective measures aimed at preventing disease e.g., vaccination. |
| Promoter | A DNA sequence, usually occurring immediately prior to an open reading frame, to which proteins can bind in order to activate transcription of the gene. |
| Radiotherapy / Ionising radiation | The use of high energy X-rays or other types of ionising radiation to kill cancerous cells. Ionising radiation describes short wavelength or particulate electromagnetic radiation including X-rays, gamma rays, alpha particles and beta particles. |
| RNA probes | Single-stranded, labelled RNA molecules of known sequence, which are used to detect specific RNAs in a tissue sample. RNA probes detect the presence of specific oncogenic or benign HPV types in a cervical sample. |
| Stages | The stage of a cancer describes the extent of its progression within the body, based on the size of the tumor, whether it has invaded nearby lymph nodes and whether or not it has spread to other parts of the body. Cervical cancer is staged according to the FIGO (International Federation of Gynaecology and Obstetrics) criteria. There are four stages: I, II, III and IV. |
| Transcription | The mechanism whereby a DNA sequence is converted into RNA, which can then be translated into a protein. |
| Transient | A transient infection is cleared by the host immune system. In the case of HPV, a transient infection is usually defined as lasting six months or less. |
| Transformation zone | The area of the cervix where columnar cells are replaced by squamous cells, in a normal process, over long periods of time. |
| Triage | The process whereby the best treatment course is selected on the basis of available information. HPV DNA testing can assist in the triage of women with abnormal or inconclusive cervical screening results. |
| Tumour | An abnormal mass of tissue that is the result of cells growing and dividing in an uncontrolled manner. Tumours may be benign (non-cancerous) or malignant (cancerous). |
| Ultrasound | A technique used to visualise tumours occurring within the body. High-energy sound waves (ultrasound) are bounced off the internal organs and tissues, and an image of the body is created from their echoes. |
| Vaccination | The artificial induction of immunity to an infection or disease. |
| Vascularisation | The formation of blood vessels. |
| Viraemia | The presence of a virus in the blood stream. |
| Virion | A single, complete virus particle. |
| X-rays | High-energy beams of ionising radiation that pass through most of the body tissues but are reflected by denser areas such as bones. |
| Years of life lost (YLL) | A measurement of the total number of years of life that are lost due to a disease during a given time period and across a specified population. YLL figures are based on mortality data and age at death. The relative weighting of life at different ages helps to evaluate the effects of a disease on the economic productivity of individuals and their social roles, particularly child care. |