Ch.11 Cancer Biology Clinical Flashcards
“My uncle has liver cancer and so does my mom,” says Sandi Mauntz. “But the doctor said his cancer is primary and hers is metastatic. What does that mean?”
Cancer starts in one location, and then cancer cells can break off and travel to a new location, where they form another tumor, in a process called metastasis. The first place where cancer starts is called the primary tumor. So the cancer in your uncle’s body started in his liver. The cancer in your mother’s body started in another location, and cells from that primary tumor broke off and moved to your mother’s liver. That is why her liver cancer is called metastatic.
Mr. Winslow has small cell carcinoma of the lung, with persistent hyponatremia. “The doctor told me that cancer cells are making a hormone and said ‘paraneoplastic syndrome,’ but then her beeper rang and she had to leave in a hurry,” says Mrs. Winslow. “Please finish the explanation. What hormone? What does paraneoplastic syndrome mean?”
Some cancers release substances into the blood that cause effects elsewhere in the body. Those effects are called paraneoplastic syndromes. Your husband’s cancer cells release a substance called antidiuretic hormone (ADH) into the blood that is causing a paraneoplastic syndrome. The word ectopic means that the hormone ADH is being released from an abnormal place, your husband’s lung cancer. Normally, the pituitary gland releases ADH, but feedback controls keep it from making too much ADH. The cancer cells do not have feedback controls, so they keep releasing too much ADH.
“What is the Warburg effect?” says Nurse Davidson, who is reading a journal article about new cancer treatments. “What does that mean?”
The Warburg effect describes how cancer cells derive their energy for rapid cellular growth by metabolizing large amounts of glucose rapidly by glycolysis, even in the presence of oxygen (aerobic glycolysis). That is different from normal cells, which rely on glycolysis for most of their energy only when there is not enough oxygen (anaerobic glycolysis).
“Now please explain the reverse Warburg effect,” says Nurse Davidson. “Does that mean the cancer cells make glucose instead of burning it for energy?”
No, the reverse Warburg effect does not involve cancer cells making glucose. They need energy to fuel their rapid growth. The reverse Warburg effect involves cancer cells influencing tumor-associated fibroblasts to use glycolysis, even in the presence of oxygen (aerobic glycolysis). The tumor-associated fibroblasts then secrete metabolites that the cancer cells can use for fuel.
Nurse Kapoor asks, “Why do so many of our cancer patients have hypercalcemia, even when they do not have bone metastases?”
Cancer cells often secrete chemicals, such as parathyroid hormone-related peptide, that circulate to bone and cause bone resorption, which releases calcium into the blood.
(Ms. Lavenia Smith, age 67, went to see a physician because of dyspnea and a chronic cough. When asked, Ms. Smith stated that she has smoked cigarettes since she was a teenager. Pulmonary function tests show a definite blockage in her airflow; a chest radiograph shows a lesion; and bronchoscopy washings contain malignant cells. Her diagnosis is bronchogenic lung cancer. Histologically, it is a squamous cell carcinoma.)
Why did Ms. Smith have a blockage in her airflow?
Bronchogenic carcinoma arises in the lining of the airways and can cause an obstruction as it grows inward into the lumen.
(Ms. Lavenia Smith, age 67, went to see a physician because of dyspnea and a chronic cough. When asked, Ms. Smith stated that she has smoked cigarettes since she was a teenager. Pulmonary function tests show a definite blockage in her airflow; a chest radiograph shows a lesion; and bronchoscopy washings contain malignant cells. Her diagnosis is bronchogenic lung cancer. Histologically, it is a squamous cell carcinoma.)
Did Ms. Smith’s lung cancer metastasize from cancer in another location in her body, or did it arise in her lungs? What information provides this answer?
Her cancer arose in her lung. The term bronchogenic means that the tumor arose in the bronchi.
(Ms. Lavenia Smith, age 67, went to see a physician because of dyspnea and a chronic cough. When asked, Ms. Smith stated that she has smoked cigarettes since she was a teenager. Pulmonary function tests show a definite blockage in her airflow; a chest radiograph shows a lesion; and bronchoscopy washings contain malignant cells. Her diagnosis is bronchogenic lung cancer. Histologically, it is a squamous cell carcinoma.)
Why did Ms. Smith develop dyspnea?
Obstruction to airflow due to the tumor in the airway and compression of lung tissue from an expanding tumor both can contribute to dyspnea in people who have bronchogenic carcinoma.
(Ms. Lavenia Smith, age 67, went to see a physician because of dyspnea and a chronic cough. When asked, Ms. Smith stated that she has smoked cigarettes since she was a teenager. Pulmonary function tests show a definite blockage in her airflow; a chest radiograph shows a lesion; and bronchoscopy washings contain malignant cells. Her diagnosis is bronchogenic lung cancer. Histologically, it is a squamous cell carcinoma.)
The lining of the bronchi normally is pseudostratified columnar epithelium, not squamous cells. Why did Ms. Smith’s cancer develop from squamous cells?
Repeated exposure to cigarette smoke causes squamous metaplasia in the bronchi, which means that the normal pseudostratified columnar epithelial cells are replaced with squamous cells that can survive more easily in the harsh environment. One or more of these squamous cells eventually accumulated enough mutations to become malignant.
(Ms. Smith is scheduled for surgery, followed by radiation therapy and chemotherapy. Surgery will remove the bulk of the tumor, and the radiotherapy is expected to shrink remaining lung tumor cells. The chemotherapy is aimed at metastatic liver tumors that were discovered. Ms. Smith has stopped smoking.)
Why did Ms. Smith’s physician order a liver scan when he discovered that Ms. Smith had bronchogenic carcinoma?
Bronchogenic carcinoma frequently metastasizes to the liver.
(Ms. Smith is scheduled for surgery, followed by radiation therapy and chemotherapy. Surgery will remove the bulk of the tumor, and the radiotherapy is expected to shrink remaining lung tumor cells. The chemotherapy is aimed at metastatic liver tumors that were discovered. Ms. Smith has stopped smoking.)
Why had Ms. Smith’s cancer metastasized before she had enough signs and symptoms to seek out a physician?
Bronchogenic carcinoma usually does not cause symptoms in its early stages; by the time the cancer is discovered, the tumor may be advanced and there has been time for metastasis to occur.
(Mrs. Gillespie died from stage IV colon cancer. Her son Tom, age 52, was diagnosed with stage I colon cancer that was treated successfully with surgery and chemotherapy. Mr. Gillespie has a lot of questions as he reflects on his experiences.)
“My mother had stage IV cancer and she died; I had stage I cancer and I survived,” says Mr. Gillespie. “Obviously stage IV is worse, but how do the doctors determine what stage a cancer is?”
They look at the size of the tumor, how many lymph nodes it has involved, and if it has spread to distant locations in the body.
(Mrs. Gillespie died from stage IV colon cancer. Her son Tom, age 52, was diagnosed with stage I colon cancer that was treated successfully with surgery and chemotherapy. Mr. Gillespie has a lot of questions as he reflects on his experiences.)
“I remember the oncologist telling my sister and me that our mother’s cancer had spread to her liver. What was that fancy ‘meta-’ word that he used?” asks Mr. Gillespie
Metastasis. That means the cancer cells have traveled in the blood or the lymph and have formed a new tumor distant from the primary one. The liver is a common place for cancer metastasis.
(Mrs. Gillespie died from stage IV colon cancer. Her son Tom, age 52, was diagnosed with stage I colon cancer that was treated successfully with surgery and chemotherapy. Mr. Gillespie has a lot of questions as he reflects on his experiences.)
Mr. Gillespie asks, “Does everybody who gets liver cancer have cancer someplace else first?”
No, cancer can arise in the liver, just as it can arise in the colon. Cancer arises when the genetic material in the cells develops mutations that cause the cells to multiply in an uncontrolled fashion and develop the characteristics of cancer cells.
(Mrs. Gillespie died from stage IV colon cancer. Her son Tom, age 52, was diagnosed with stage I colon cancer that was treated successfully with surgery and chemotherapy. Mr. Gillespie has a lot of questions as he reflects on his experiences.)
“I am grateful that I survived chemotherapy,” says Mr. Gillespie. “I knew I would lose my hair, but I was surprised when I got those painful sores in my mouth. How did the chemo cause the sores?”
Chemotherapy drugs kill cells that are dividing rapidly. That kills cancer cells, but it also kills some normal cells like the cells in the lining of your mouth. So the drugs that helped get rid of the cancer also made those painful sores. Now that you are no longer receiving chemotherapy, your body has repaired the lining of your mouth.
