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)
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~
https://movie-screencaps.com/moulin-rouge-2001/