synthesizing keratin, and bile synthesis by hepatocellular carcinoma are several samples
of good differentiation [23].
Loss of differentiation is called anaplasia, and the tumors originating from these cells
are called anaplastic tumors. Morphological findings belong to anaplastic tumors: pleo
morphism (tumor cells, nucleus, and shapes, dying parameters are different), anomalies
in nucleus morphologies (increase in active RNA synthesis), increase in mitosis fre
quency, and loss of polarity and orientation. Irregular proliferation in epithelial cells
characterized with pleomorphism, hyperchromasia, nucleomegaly, abnormal mitosis, is
called dysplasia. Dysplasia is usually formed on a metaplasia basis and could disappear if
the predisposing factor is removed, and in case it is not affecting all the epithet layers. If it
is affecting all layers of the epithelium without basal membrane invasion, it is named
grade 3 dysplasia or in situ carcinoma. Whenever the basal membrane invasion is seen, it
is called invasive carcinoma [23].
There are roles of inheritance as well as environmental factors in the basis of tumor
igenesis. The role of inheritance is well known for several tumors. Cancers with genetic
predispositions usually appear at younger ages, with multi-centric retention, and bilateral
foci with worse prognoses.
Geographical conditions are blamed for some types of cancer etiologies such as gastric
carcinoma, seen more in Japan, whereas Burkitt lymphoma is mostly diagnosed in Africa
[24]. Besides geographical factors, chronic alcohol use and smoking increase some types
of cancers in particular. There are also occupational carcinogens such as asbestosis, ar
senic, benzene, beryllium, cadmium, and vinyl chloride that are causing cancer in the
patients who have regular exposure due to their working conditions [23].
Early diagnosis is sometimes lifesaving for several cancers. Therefore, screening stra
tegies come along with these purposes. Some screening tests are designed for all the
population, whereas some are specified for the increased risk group. Colorectal cancer,
cervical cancer, and mammary cancer are the cancer types with screening protocols for all
the population. Patients applying to physicians receive a physical examination at first.
The most important finding would be lymphadenopathies. Besides lumps, symptoms
such as major weight loss, tiredness, or night sweats could be a clue, and changes in skin
color and palpable organs may also give an idea for further investigations.
Laboratory experimental results such as urine and blood analysis may give an idea
about the causes of the symptoms. Sometimes, specific tumor markers might be re
quested due to the suspicion of the physician according to the performed physical ex
amination. Calcitonin, catecholamine, and human chorionic gonadotropin are hormones
that may be used as tumor markers in medullary thyroid cancer, pheochromocytoma,
related tumors, and trophoblastic tumors, respectively. Carsino-embryogenic antigen
and alpha feta protein are oncofetal antigens that are also used as tumor markers on
colon, pancreas, gastric, lung carcinoma, and hepatocellular carcinoma, respectively [25].
Another tool that is used for the diagnosis is imaging tests, such as computerized to
mography, positron emission tomography scan, bone scan, magnetic resonance imaging
(MRI), and ultrasound. For the treatment of diagnosed cancer, if there is a presence of a
solid tumor, surgery may come up as an option of treatment to decompress the organs
near the tumor. Chemotherapy and radiation therapy are the other options of treatment
according to the tumor’s sensitivity to those treatment modalities. In some cases, before
the planned tumor surgery, chemotherapy may be used to decrease the tumor burden
before the surgery, which is called neoadjuvant chemotherapy. Immunotherapy is an
other method of cancer therapy that makes the patient’s cells fight the cancer cells. In
immunotherapy, monoclonal antibodies are very popular by blocking the specific
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