Prof. Allison Shearer |
EL CAJON—Way down in a human body, deep inside a molecule, a cell was in the process of dividing itself. But instead of the daughter cell being an exact replica of the mother cell, it had developed a little flaw—a mutation.
Sometimes when this happens, other cells in the affected area of the body sense there is a problem, Prof. Allison Shearer said in a lecture dealing with biological issues touched upon in Pulitzer Prize winning author Siddhartha Mukherjee’s The Emperor of All Maladies: A Biography of Cancer. Mukherjee’s book is currently the subject of a “One Campus, One Book” interdisciplinary study at Grossmont College.
Shearer said the nearby cells in such cases will communicate a signal to the new cell that for the good of the body, it ought to “commit suicide” in a process scientists call “apoptosis.”
The professor urged an audience of over 100 students on Nov. 14 to all wiggle their fingers, and to raise their hands if they found their fingers were webbed together. No hands were raised. This, lectured Shearer, was because the process of apoptosis had worked while they were still developing as fetuses. As they developed, they had webbing between their fingers. Fortunately, the cells within the webbing extinguished themselves, freeing the fingers for human movement.
Apoptosis normally is an excellent defense mechanism but cancer cells have learned how to ignore the body’s signals, Shearer told students who had packed the Griffin Gate lecture hall. When figuratively told by the other cells “go kill yourself,” a precancerous or cancerous cell will respond, in effect, “uh-uh, nope, I’m going to stick around and make your life miserable,” Shearer said. Furthermore, Shearer imagined the cancer cell saying, “I’m going to keep going through my cell cycle and outgrow myself, and while I’m at it, I’m going to get blood vessels to grow in me, so I can take the nutrients that the rest of you need, and I’m going to spread my cancer elsewhere.”
The biology professor told the students that when cancer cells eventually multiply sufficiently to create a cancerous mass, “they are really good at tricking blood vessels to move into the tumors.”
If someone is having a biopsy done, and if the tumor has a lot of blood vessels, “that is a sure fire way to know that you are dealing with a cancerous mass in the body,” Shearer said.
The professor said normal cells rest when they have replicated a sufficient number of times to replace needed material such as the skin that grows back over a cut on someone’s finger. In contrast, cancer cells will keep growing and growing, and each generation of growth comes a little faster and is “a little sloppier.”
By that, Shearer said she meant that the cancer cells will not exactly replicate themselves, but will continue to mutate, making it very difficult to find a treatment that will work on them. “What is happening as you are trying to fight the cancer, the cancer is trying to stay a step ahead of you with mutations,” she said.
Her lecture explaining the fundamentals of cancer biology was the second in a six-part series that will be given over the Fall and Spring semesters in a program overseen by English Prof. Tate Hurvitz.
“Through our One Book, One Campus program we are helping students see connections between subjects they might have previously thought unrelated or to see one complex issue from a variety of perspectives,” commented Grossmont College President Sunita V. Cooke. “All of these things are important to training the next generation of entrepreneurs and workers. They are going to work in an ever-changing world with complex issues that will need this kind of critical thinking and an understanding of different perspectives.”
Another lecture by Humanities Prof. Pete Schmidt will focus on the way visual images influenced attitudes toward cigarette smoking in the 20th century.
--DHH--
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