Breast Cancer Cells
The dark blue or purple clusters of cells are the cancer cells. They are clumped together because this type of cancer cell, adenocarcinoma, has a tendency toward incomplete cell division. This leaves the cells stuck together and sometimes appear to have more than one nucleus. The rest of the smaller cells are normal red blood cells (salmon colored), and white blood cells (blue nucleus).
This slide is made from pleural fluid taken from the chest cavity of a breast cancer patient using a cytocentrifuge to concentrate the cells in the fluid directly onto the microscope slide. Properly done, this removes excess fluid and protein from the specimen as there is a piece of blotter paper around where the specimen is concentrated to absorb the excess. It results in a much better preparation that simply putting a drop of the fluid on the slide, or making a push smear would accomplish. Simply dropping the fluid onto the slide, or making a push smear, very often allows the white blood cells and cancer cells to “ball up” due to the excess protein, as the WBC are here. This makes it very hard to see the cells clearly making diagnosis difficult.
This particular preparation is a little too thick. We should have either used a smaller amount of pleural fluid, or diluted the specimen prior to cytocentrifugation. That would have made the WBC structure more clear, and separated out the RBC so you could see the individual cells, instead of the mass we have here.
The cells are that color because they have been stained with a regular hematology stain, Wright-Giemsa, to make them easy to identify. The cells are normally colorless and nearly transparent.