On the welcome page of the dictionary, three major sections are shown: Normal tissues, Cancer and Cell structure. Below the image of each section are links to introductory texts for i) normal tissue histology, ii) hallmarks of cancer, and iii) cell structure overview. For the cancer-section there is also a link to current cancer statistics (incidence, survival, etc) for Sweden and the rest of the world. Within each section there are direct links to histology descriptions of different tissue types and tumor forms as well as descriptions of cell structures.
For the 'Tissue & cell types' and 'Tumor' sections, tissue-slides stained with hematoxylin and eosin (HE) are shown at three different levels of magnification. On the top level, an overview of the whole tissue-sample is shown with boxes in black indicating where zoomed-in representative parts of the tissue are available for viewing. Clicking on these boxes will zoom in on that part to show tissue structures, cells and features in greater detail. Throughout these sections, arrows indicate relevant tissue structures, cell-types and other features.
For the 'Cell structure' section, immunofluorescent images of formaldehyde-fixed cell lines are shown. The various cell structures that are demonstrated are always shown in the green channel using an antibody found in the Human Protein Atlas. The antibody name is linked to the subcellular location summary page of the target gene. The other channels: nucleus, microtubules and endoplasmic reticulum, are always shown in the blue, red and yellow channels, respectively. The channels can be toggled on and off by clicking on the respective coloured button above the image. When applicable, the immunofluorescent images are complemented by immunohistochemically stained cells where the location of the particular cell structure is shown in brown.
A common feature for all sections is that a general descriptive text about the tissue, tumor-type or cell structure is provided when browsing a particular topic.
Female, 42 years, moderately differentiated adenocarcinoma
Cervical cancer
The cervix is the narrow, lower portion of the uterus that joins the top of the vagina. Cervical cancer is the third most common type of cancer in women worldwide. One of the most common symptoms of cervical cancer is abnormal vaginal bleeding, but in some cases there may be no obvious symptoms until the cancer is in its advanced stages.
Cervical cancer usually develops very slowly, often over a period of months and years. It initially forms as a precancerous condition called dysplasia. This precancerous condition can be detected by a Pap smear (a cytology specimen retrieved from the cervix to obtain cells that are transferred to a glass slide for staining and microscopical examination) and is completely treatable. Most women who are diagnosed with cervical cancer today have not had regular Pap smears or they have not followed up on abnormal Pap smear results. The widespread use of cervical screening programs has reduced the incidence of invasive cervical cancer by 50% or more in countries where such programs successfully have been established. However, Pap smear screening remains a challenge in developing countries such as India and China. Consequently, the incidence of cervical cancer in these countries is high.
The Human Papilloma Virus (HPV), that can spread through sexual intercourse, is the cause of nearly all cervical cancers. There are many different types of HPV and certain strains lead to high risk for developing cervical cancer. Risk factors include having sex at an early age, multiple sexual partners, smoking and poor socio-economic status.
Cervical cancers arise from cells in the transitional zone of the cervix. The transitional zone is the border between squamous epithelium, that cover the distal portion of cervix (the portio) and the columnar, glandular cells that line the endocervical channel. Most cervical cancers originate from cells that show squamous differentiation and are hence squamous cell carcinomas. Cancers arising from the columnar cells are defined as adenocarcinomas and are more rare.
The FIGO (International Federation of Gynecology and Obstetrics) staging system recognizes four stages of cervical cancer. Stage I depicts cancer limited to the cervix. Stage II denotes cervical cancer that has spread beyond the cervix but not to the lower third of the vagina or the pelvic wall. Stage III cancers have spread to the pelvic wall and/or lower third of the vagina. Stage IV tumors extend beyond the true pelvis or clinically involve the mucosa of the bladder and/or rectum. With treatment, 80 to 90% of women with stage I cancer and 50 to 65% with stage II cancer are alive 5 years after diagnosis. Only 25 to 35% of women with stage III cancer and 15% or fewer of those with stage IV cancer are alive after 5 years.
A vaccine to prevent cervical cancer is now available. In June 2006, the U.S. Food and Drug Administration approved a vaccine which prevents infection by the two types of high-risk HPV responsible for most cervical cancers. Studies have shown that the vaccine appears to prevent precancerous lesions and early-stage cervical cancer.
