Details.txt

> What is a Biopsy ?

A biopsy is a medical procedure, during which a small sample of tissue is removed from a part of the body. The sample of tissue is then examined under the microscope to look for abnormal cells. Sometimes the sample is tested in other ways. For example, it may be tested with chemical reagents to help identify abnormal chemicals in the tissue sample. Sometimes tests are done on the sample to look for bacteria or other germs.



> What is Cancer ? Define Breast Cancer.

Cancer is the uncontrolled growth of abnormal cells anywhere in a body. These abnormal cells are termed cancer cells, malignant cells, or tumor cells. These cells can infiltrate normal body tissues. Many cancers and the abnormal cells that compose the cancer tissue are further identified by the name of the tissue that the abnormal cells originated from (for example, breast cancer, lung cancer, colon cancer). Cancer is not confined to humans; animals and other living organisms can get cancer. 

Breast cancer starts in the cells of the breast as a group of cancer cells that can then invade surrounding tissues or spread (metastasize) to other areas of the body.Cancer begins in the cells which are the basic building blocks that make up tissue. Tissue is found in the breast and other parts of the body.  Sometimes, the process of cell growth goes wrong and new cells form when the body doesn’t need them and old or damaged cells do not die as they should.  When this occurs, a build up of cells often forms a mass of tissue called a lump, growth, or tumor.

Breast cancer occurs when malignant tumors develop in the breast.  These cells can spread by breaking away from the original tumor and entering blood vessels or lymph vessels, which branch into tissues throughout the body.

Breast cancer has been observed to have 246,000 new estimated cases, 18% of all cancer estimated cases, a year(2015-16) followed by 40,000 deaths.



> How is Biopsy related to detection of Cancer ?

Biopsies are often important to diagnose cancer. A biopsy is commonly done if you have a lump or swelling of a part of the body where there is no apparent cause. In these situations often the only way to confirm whether the lump is a cancer is to take a biopsy and look at the cells under the microscope. Cancer cells look different to normal cells.



> What is the origin of the dataset ?

This breast cancer database was obtained from the University of Wisconsin Hospitals, Madison from Dr. William H. Wolberg. He assessed biopsies of breast tumours for 699 patients up to 15 July 1992; each of nine attributes has been scored on a scale of 1 to 10, and the outcome is also known. There are 699 rows and 11 columns.

16 values are missing from the Bare Nuclei column. In order to avoid any hassle, these 16 records were deleted; else introduction of unruly data may affect the predictibility of the model.

P. M. Murphy and D. W. Aha (1992). *biopsy.csv* , UCI Repository of machine learning databases. [Machine-readable data repository]. Irvine, CA: University of California, Department of Information and Computer Science.



> What are the terms used in the CSV File ?

Benign Cells are non-cancerous. Malignant Cells are cancerous. They are described as Class and are the values to be predicted.

Clump Thickness: Benign cells tend to be grouped in monolayers, while cancerous cells are often grouped in multilayers. Hence thickness of the lump or tumour may throw some light on the type of cells.

Uniformity of Cell Size/Shape: Cancer cells tend to vary in size and shape oddly compared to normal cells. That's why these parameters are valuable in determining whether the cells are cancerous or not. 

Marginal Adhesion: Normal cells tend to stick together. Cancer cells tends to loose this ability. So loss of adhesion is a sign of malignancy. 

Single Epithelial Cell Size: It is related to the uniformity which is mentioned. Epithelial cells that are significantly enlarged may be a malignant cell. 

Bare Nuclei: This is a term used for nuclei that is not surrounded by cytoplasm (the rest of the cell). Those are typically seen in Benign tumours. 

Bland Chromatin: Describes a uniform "texture" of the nucleus seen in benign cells. In cancer cells the chromatin tend to be more coarse. 

Normal Nucleoli: Nucleoli are small structures seen in the nucleus. In normal cells the nucleolus is usually very small if visible at all. In cancer cells the nucleoli become more prominent, and sometimes there are more of them.