The Many Forms of Cancer

 
Introduction:

 Cancer in its most basic and fundamental terms is a disease where abnormal cells begin to divide uncontrollably and destroys body tissue in the process. It can originate anywhere in the body and is made up of trillions of cells. Normal healthy human cells grow and divide to form new cells when the body demands or needs them. As cells grow old, they become damaged, and eventually die off. New cells then take their place. This is not the way cancer cells progress through their life span. These cells become increasingly abnormal, old, or damaged surviving even when they are supposed to die and be replaced with new cells. The cells divide without pause forming growths known as tumors.(B)

Cancers can develop into solid tumors which consists of masses of tissue. Leukemia on the other hand, is a cancer of the blood that does not form into a solid tumor. Malignant cancerous tumors tend to spread or invade neighboring tissues. As they grow, some of the cancer cells break off and travel to other regions in the body through the blood or lymph system where new tumors can form.  Then there are benign tumors that do not spread or invade nearby tissues. They tend to be large and when removed they do not grow back. However, benign brain tumors can be life threatening.(B)

It is commonly classified by the organ or organ system according to its point of origin. The shape of cancer cells give scientists clues about the behavior or progression of that specific cancer. Their shapes vary from being super flat, ring like shape, or resemble the appearance of miniature oats. The different shapes allowed for each cancer to be diagnosed and treated differently. With greater amount of time spent on genetic research, the more knowledge we will have about these cells and the cancers they give birth to. There are 10 cancers that are located in 8 organs, the blood, and lymphatic system which accounts for over 70 percent of cancer cases in the US (new and old). (A)

 Lung Cancer:

The human lungs are complex in structure, making tumors in the lung difficult to detect. This allows the tumor enough time to spread to neighboring tissues. Unfortunately, only 16 percent of tumors in the lung are discovered by physicians before they have reached, metastasis, the bloodstream or lymphatic system to make root in other organs and tissues.(A)

Small cell and non small cell are the two types of cancer cells that form in the lung. Small cell or oat cell have very little cytoplasm or liquid inside. Small cell lung cancers form inside the bronchi (i.e. the lung's branches that function as airways) are aggressive as they metastasize with great rates. Smokers are at highest risk for this type of lung cancer cells. With non small cells, 90 percent of lung cancers are this type where 40 percent of these are adeno-carinomas. This type of carcinoma, most common form of cancer, begins in cells that secrete mucus as well as other substances. Non small cell lung cancers are located in the flat cells of bronchi's epidermoid lining (squamous cell carcinomas). The rest are known as large cell carcinomas. (A)

Prostate Cancer:

Prostate cancer is known for its slow growth and if detected early can cause no harm if caught in its early stages. Treatment for prostate cancer tends to give patients undesirable side effects such as incontinence and impotence. It is strongly recommended that once men reach the age of 50 should begin having prostate screenings. African American men or those who have close relatives diagnosed with prostate cancer before the age of 65 are at higher risk and should discuss the possibilities of prostate cancer with their physician as early as the age of 45. (A)

Majority of prostate cancers, about 95 percent, form in the gland cells of the prostate where it can take different forms. These adenocarinomas can be foamy, colloid, signet-ring as their nuclei are pushed in the periphery making them take the form of a ring.Under a microscope, well differentiated cancer cells recieve a low grade from pathologists because they look like healthy cells. Those cells that are poorly differentiated cells tend to score much higher and are known to spread much quicker. Then there are prostate cancer cells are small cell carcinomas. (A)

This form of prostate cancer is aggressive and extremely difficult to detect because they do not affect the production of PSA protein (seen in blood samples). In contrast to adenocarcinomas, these cancer cells are small and round. The third type of prostate cancer cells are squamous cell carcinomas. They are nonglandular, affect the lining of the prostate, and is difficult to detect. The reason why it is so hard to detect is because the PSA protein remains at the same levels as a healthy individual. This is the most aggressive form of prostate cancer with an average survival rate of about 12 months to live. However, this form is very rare in which about less than one percent of prostate cancers. (A)

Breast Cancer: 

The most common form of cancer is breast cancer. Men and women can both develop breast cancer. The most common sign of breast cancer are lumps in the breast area which is caused by many different factors, one of them being tumors. The lobules, cells that produce milk, is usually where tumors begin. When these tumors are benign, it means that they remain in the area they begin and do no harm to the body. When tumors expand, reaching neighboring tissues, they are now considered malignant. Breast cells use receptors to convert chemical signals into action potentials within the cell. Because of this, these receptors are a defining feature of breast cancer. How these receptors behave in reaction to signals within the cell will be determining what is the most effective treatment for the patient. (A)

Healthy or normal breast cells as well as some breast cancer cells have receptors that attach to estrogen and progesterone. Roughly, 74 percent of breast cancers are ER (estrogen receptor) or PR (progesterone receptor) positive. This means that when breast cancer cells attach themselves to these hormones, it stimulates the tumor to grow. Whenever breast cancer is ER/PR positive it responds to hormone treatment which can block the hormones receptors. Another receptor for protein HER2(for human epidermal growth factor receptor 2) will also fuel cell growth. HER2-positive cancers are more aggressive than HER2-negative ones, but they are also more sensitive to certain drugs that block the HER2 protein. (In cancer, sensitivity is a good thing. The more sensitive the cancer is, the more likely it is to respond to the treatment.)

Then there is a third type of cancer that are known as 'triple negative' because they do not have any of the receptors mentioned above. These cancers are known for spreading quickly and are more difficult to treat. 12 percent of all breast cancers are triple negative. They are twice as likely to develop in black women as apposed to white women and even more likely to be found in women with mutations on their BRAC1 tumor suppressor gene. (A)

Colon Cancer:

Colon cancers start out as small already formed clumps of cells called polyps. They are found in mucus producing gland cells that line the colon. Roughly, 33 percent to 50 percent of patients have these polyps in their colons. Less than 10 percent of these polyps become invasive cancer (adenocarcinomas). To determine the severity of the adenocarcinoma, physicians look at the differentiation that is the process of immature cells maturing. Cancer cells usually look like the younger versions of healthy cells. Tumor cells that are poorly differentiated are more advanced in the stages of cancer. There are drug therapies that used to attack cancer by pushing these younger looking cells into maturity. (A)

When cancer cells are found in the colon's veins or arteries, this is known as vascular invasion. When the tumor enters the lymphatic system, it is called a lymphatic invasion. Once these cancer cells move into these systems, circulating throughout the human body, there is a very high risk that the cancer will find its way to new parts of the body. With mucinous tumors, they spread quickly existing in pools of excess mucus. When dealing with signet ring shaped tumor cells, you can see the mucus pushing the cell's nucleus over to one side giving the cell its distinctive shape. Cancers are very smart and adaptable to their environments as they quickly learn how to hide as time progresses, specifically those tumors that are solid. There are trials being conducted where a cancer vaccine makes use of the dendritic cells (messenger blood cells in the immune system) trained to activate other cancer fighting cells, which are then reintroduced in the patients body. (A)

 Cancer of the Lymphatic System:

Whenever a cancer begins in the lymphatic system, most commonly located in the lymph nodes (oval organs that filter invasive particles such as viruses, bacteria, and cancer) the cancer is known as lymphoma. Lymphatic system functions in collecting fluids, wastes, and invasive particles from regions in the human body outside of the blood stream. Lymph vessels or nodes function similar to veins however, instead of carried blood they circulate lymph. Lymph vessels are filled with WBCs called lymphocytes. Patients suffering with lymphoma have weakened immune systems which subsequently makes them very high risk for infections. The way in which the human body works is a network of interconnected body systems of lymph and blood. These are also the pathways in which cancer often uses to spread during metastasis to various ares of the body. Because of this, it is clear to see why and how the lymph system can be so complicated. (A)

Hodgkin lymphomas account for 95 percent of all Hodgkin (i.e. classical Hodgkin). These enlarged cancerous lymphocytes, 'Reed-Sternberg cells', make up 5 percent of the cells that resemble popcorn known as 'popcorn cells'. Majority of cancer cells are ultra sensitive to damage of DNA and is how cancer is often treated with chemotherapy. Chemotherapy uses agents to attack the bonds that form DNA's double helix, breaking the strands, stopping the cancer cells from multiplying and killing them.With Non-Hodgkin lymphomas, however, are much more common than Hodgkin lymphomas.
New treatment options for lymphomas involve using the patient's T-cells (immune cell located in blood) to be genetically engineered to produce special receptors on their surface called CARs (i.e. chimeric antigen receptors). These new cells are able to recognize proteins on tumor cells that have hidden the cancer from the body's immune system. Many immuno-therapies work in a similar fashion as they are programmed to unmask the cancer so that the immune system can recognize and kill off the cancer. (A)

 

 

 Cancer of the Bladder: 

If diagnosed with cancer in the bladder, the first symptom is blood in the urine occurring in 80 percent of patients with bladder cancer and is much more common in white men. Even after proper treatment, the cancer spreads to the urinary tract, linings of the kidney, ureter, and urethra. Researchers have recently discovered that between treatments while the cancer is building its resistance to treatment where it is vulnerable to new treatment. There is gene therapy where modified viruses infect the cells of bladder cancer, marking them with a hormone that sends a chemical signal to the immune system to attack them. Bladder cancers that develop in the inner most lining of the bladder is known as urothelium, where the cells are known to bunch and stretch depending on the bladder's status of being full or empty. Because of this, these cells have contact with urine and the chemicals found in urine that can cause cancer. (Chemicals from tobacco smoke are a possible cause of bladder cancer, as are arsenic and diesel exhaust.) Superficial bladder cancer appears as small growths that look like cauliflower in the lining of the organ. This is known as non muscle invasive and is in its early stages. It can progress to invasive levels where there is a high risk of metastasizing. (A)

 

 Skin Cancer, 'Melanoma' : 

Basal cell and squamous cell skin cancers are the most common types of skin cancer. They are found so early and so often that they are not required to be reported to cancer registries in N. America.

For early detect of skin cancer, one can use the ABCDE rules. A is for asymmetry (when one half of the mole doesnt match the other half), B is for border irregularity (ragged, notched, or blurred edges); C is for color (not uniform, with shades of tan, brown, or black in one mole); D is for diameter greater than 6 milli­meters (about the size of a pencil eraser); and E is for evolution (in other words, change). Mela­nomas represent about 1 percent of all skin-cancer cases but nearly all skin-cancer deaths, because they grow and metastasize so much faster than other forms of skin cancer. Generally, one should look for new or changing skin growths especially those that look different from other moles.(A)

The most common form of melanoma to date is superficial spreading, occuring to 70 percent of all patients with skin cancer. At first, it appears as a benign mole before it begins to flatten out or even become slightly raised from the skin surface as a discolored patch with irregular borders making it asymmetrical. Individuals with 'Lentigo Malina' is located and remains located near the skin surface, is discolored and commonly seen in elderly people and chronically exposed to the sun such as individuals who live in Hawaii or tropical islands. When the regions of ones skin appears black or brown in their discoloration beneath nails, feet soles, hand palms is known as Acral Lentiginous. It is usually seen in African Americans and Asians. Finally, there is nodular skin cancer which is the most aggressive melanoma and many times found to be invasive when diagnosed. (A)

Thyroid Cancer:  

Individuals that are diagnosed with thyroid cancer either find a lump in their neck or has feelings of tightness in the throat, has a difficult time breathing and swallowing. Thyroid tumors are commonly known to be slow progressing where only about 5 percent grows aggressively becoming a major risk of reaching other organs in the body. Although thyroid cancer is very treatable, this type of cancer does not respond well to chemotherapy. There are new targeted drugs that work really well for patients with thyroid cancer. Kinase inhibitors blacks certain enzymes similar to thyroid cancer and inhibits the growth of blood vessels. The way many tumors of cancers surivive in the body is through angiogensis where it is able to form new blood vessels. Majority of thyroid cancer is differentiated where the cancer mutation does not look different from a typical thyroid cell. DTC is divided into four groups where one of the subsets are known as the encapsulated follicular variant of papillary thyroid cancer. Women and younger individuals usually develop this form but is very treatable. When one has an inherited abnormality located in the specific gene, RET, is known as medullary thyroid. Individuals that have this abnormal RET gene which leads to medullary thyroid cancer have their thyroid removed as a preventative step. (A)

Cancer of the Kidneys:

The kidneys function in filtering blood transforming excess water, salt, and other waste products into urine. Blood enters this filter through renal arteries and urine exits through the ureter at the renal pelvis. Renal cells that line the tubes inside out of the kidney is where cancer of the kidney first appears. Resistant to chemotherapy, researches have found success with drugs that target the tumors called 'adjuvant therapy' given to patients after surgery. This drug attacks the genetic mutations that is the cause of the tumor's conintuous growth. Clear cell kidney cancer or renal cell carcinoma (RCC) accounts for 75 percent of this type of cancer. Similar to many other cancer cases, it is difficult to diagnose in its early stages.

 

 

 

The very first symptoms are blood in urine or lump in abdomen. With papillary RCC there are two types, Type I and type II. Type I makes up a total of 5 percent of cases is inherited in the gene MET from a parent drastically increases the risk of developing cancer in the kidneys. Inherited genetics can be found in the germline cells or reproductive cells which differ from adult or somatic cells. The remainder of cases, about 85 percent, progress from a sporadic mutation in somatic cells. Those that are inherited mutations in germline cells make up the remainder of cases. When discussing the sequencing of somatic cells the discussion is really about genetically sequencing cancer. Cancers, however, that are Type II Papillary RCC have distinct inherited risks that can be found in the germline cell that is being sequenced. (A)

 

Cancer of the Blood, 'Leukemia':

Blood stem cells develop into either lymphoid stem cells or myeloid stem cells. Lymphoid stem cells develop into lymphocytes, a form of WBCs whereas, myeloid stem cells can develop into bone-marrow based blood cells such as platelets. In 1994 the discovery of cancer having stem cells was first discovered in acute myeloid leukemia. Majority of leukemia cases bein in immature blood stem cells that are located in the bone marrow. Leukemia takes two forms, either acute or chronic. Whenever leukemia is rapidly progressing this is known as acute leukemia. (A)

Chronic leukemia on the other had does not progress in a similar rate, can be controlled, and individuals suffering from this form of leukemia can live with the illness for years to decades. Whenever there is a cancer of the lymphocytes where the WBCs fight any infections within the body it is known as chronic lymphocytic. With relapsed chronic lymphocytic leukemia (CLL) it is much more difficult to treat as the tumors become resistant to previously used treatments such as chemotherapy. Most recently, a new set of drugs which target specific gene mutations that are in relation to chemoresistance can slow the cancer's progression and from reaching other areas in the body. (A)

Young children are also at risk for leukemia, especially 'acute lymphoblastic leukemia' as it is the most common form to occur in children. Treatment involves chemotherapy of which the survival rate is higher than in adults. The most difficult part of treatment of cancers is knowing how many cancerous cells are still within the body after treatment is finished. Using a polymerase chain reaction test can identify trace amounts of cancer cells based on the cancer’s gene mutations (aka: its genetic fingerprint). (A)

 Concluding Remarks:

Cancer causes the bodys' cells to lose their ability to control their own growth and the body has a difficult time distingquishing between canerous cells from healthy cells. This is why treating or finding a cure for cancer is so difficult. Cancer has the ability to forever mutate to its surroundings making cancer a very tricky disease. The more knowledge and understanding there is about genetics, the higher the probability in beating this ever changing foe. Physicians are becoming increasingly skilled at finding cancer, improving treatment, and incident rates.The better the screening for cancers is, the better the chances for survival are.

Links:
(A) http://www.nytimes.com/interactive/2016/05/11/magazine/cancer-origin.html?_r=0
(B)http://www.cancer.gov/about-cancer/what-is-cancer

*Please note! These images are not mine. They were found on various tumblr sites! If any are yours please let me know so that I can give you credit for them! Also the people in the images have no relation to the diseases, illnesses, or cancers I write about. Thanks so much & enjoy~
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