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NEL Cell Division 589

Chapter 17

Identification of a Cancer Cell

Purpose

To identify cancerous cells and to recognize the differences

between cancerous and non-cancerous cells

Materials

light microscope

lens paper

prepared slide of squamous cell carcinoma

Procedure

1. Clean the microscope lenses with lens paper. Rotate
   the revolving nosepiece to the low-power objective
   lens. Place the slide of the carcinoma on the stage of
   the microscope and bring the image into focus using
   the coarse-adjustment knob.


2. Locate the dermal and epidermal layers. Draw a line
   diagram showing the position of the epidermal and
   dermal cell layers. Determine and record whether the
   cells of the epidermis are invading the dermis.


3. Rotate the revolving nosepiece to the medium-power
   objective lens. Locate a cancerous cell.Figure 1is an
   example of cancerous cells. Use the fine-adjustment
   knob to bring the image into focus. Observe how
   cells of the carcinomas have a much larger nucleus.
   They appear pink in colour and often have an
   irregular shape.
   4. Rotate the nosepiece to high-power magnification,
   and bring the image into focus using the fine-
   adjustment knob.
   5. Estimate and record the size of the cell, in
   micrometres (μm).
   6. Estimate and record the size of the nucleus of the
   same cell, in micrometres (μm).
   7. Rotate the revolving nosepiece to the medium-power
   objective lens and locate a normal cell. Rotate the
   nosepiece to the high-power objective lens, and bring
   it into focus with the fine-adjustment knob.Figure 2
   is an example of normal cells.

Purpose Design Analysis

Problem Materials Evaluation

Hypothesis Procedure Synthesis

Prediction Evidence

INVESTIGATION 17.2 Report Checklist

Figure 1

8. Repeat steps 5 and 6 for the normal cell.

Analysis

(a) Using the formula below, determine the nucleus-to-

cytoplasm ratio for the cancerous cell and for the

normal cell.

Evaluation

(b) Compare the cancerous and normal cells in a table

similar to Table 1.

Table 1

Cell type Cell size Nuclear shape Nuclear size Nucleus-to-cytoplasm ratio

normal cell

cancerous cell

Figure 2