TUMOR ASSOCIATED ANTIGEN- Lung Cancer

Lung cancer is a deadly disease when diagnosed in advanced clinical stages. Unfortunately, due to the nonspecific symptoms of this disease in its early stages, by the time patients go to the clinic, it is usually at stage III or IV (Anagnostou, & Brahmer, 2015). At these stages, it is poor survival at five years. That is why current and future trends regarding lung cancer aim at carrying out prevention policies in the population; to promote healthy lifestyles. To encourage the cessation of tobacco use, particularly in young people and young adults; to spread the usual practice of exercises and to eat a healthy diet; to avoid contact with secondhand smoke; to avoid exposure to environmental toxins.
On the other hand, new molecular and genetic knowledge, technological development, new epidemiological evidence, new diagnostic models, and new therapeutic weapons have allowed better control of the disease, with the prospect of finding a favourable solution in the medium term. In the very early stages the surgery is curative in high percentages (Anagnostou, & Brahmer, 2015). With the advent of minimally invasive surgery; Video-thoracoscopy and robotics surgery has managed to minimize pain, reduce the number of hospitalization days, and improve survival (Zappa & Mousa, 2016). Today, besides, there are new types of non-surgical treatment with organ preservation, such as directed radiation and biological treatment (using new therapeutic targets). The repair of damaged DNA and its restitution (with the use of Microarrays) is a promising future in the future management of lung cancer. Nanotechnology is still promising in the field of oncology.
Therefore, it is necessary to know the epidemiology of lung cancer, without neglecting the genetic and molecular aspects that are part of the genesis, development, prognosis and survival of this disease. Concerning tumour markers, it should be known what new diagnostic techniques, their application, advantages and benefits are, emphasizing those that help early diagnosis. The therapeutic alternatives and the advances that have been achieved in this field should not be left unmentioned (Anagnostou, & Brahmer, 2015). As a result, the analysis of the epidemiology shows the association with specific genetic configurations between males and females.
Epidemiology
In the world, the most frequent cancer in both sexes is lung cancer, followed by breast, colon and rectum, stomach, and liver. In males, lung cancer occupies the first place, then the prostate, colon and rectum, stomach, and liver (Singhal et al. 2016). In females, it leads to breast cancer, followed by colon and rectum, cervix, lung, and stomach. In 2004, the incidence of lung cancer was 1,092,056 new cases in men worldwide, in women, this value was 427,586, which represents slightly less than half of the prevalence in men (Anagnostou, & Brahmer, 2015). For this same year the registered mortality was 948 993 men and 427 586 women, 22.5 and 12.8% of the total cases in men and women respectively.
The essential carcinogen for lung cancer is cigarettes, and there is a direct linkage of up to 90% in men and 85% in women. The relative risk for lung cancer is 17.2 for men and 11.6 for women. Cigarette smoke contains more than sixty recognized carcinogens, among the best known, are nitrosamines, benzopyrenes, and radon radioisotopes, all with the ability to alter DNA and, consequently, contribute to carcinogenesis (Anagnostou, & Brahmer, 2015). That is why today it is accepted that the population at risk for lung cancer is made up of people over 50 who have smoked at least 20 cigarettes per day for at least ten years.
On the other hand, it has been documented through epidemiological studies, that there is a link between domestic wood smoke and lung cancer. This association is due to harmful particles such as phenols, acrolein, cresols, and acetaldehyde (Zappa & Mousa, 2016). The carcinogenic effects after exposure to wood smoke or animal faeces (dung) have similar effects on p53 and expression of the MDM2 protein. Radon is another known carcinogen, which occurs when uranium breaks down naturally in soil, stones, and water. It is colourless, odourless and tasteless, and also radioactive.
Other factors to take into account concerning lung cancer are genetic aspects, family cancer terrain, and exposure to particles of matter. Additionally, the exposure to uranium, pesticides, asbestos, polycyclic aromatic hydrocarbons, and arsenic the human papillomavirus also contributes to the disease (Anagnostou, & Brahmer, 2015). There are also scientific publications that use the term scar tumour to name those tumours. The result is the relationship of the malignant degeneration of a lung scar and peripheral tumours with histology related to adenocarcinoma.
Tumour Associated Antigen
The Epithelial Membrane Antigen (EMA) is a 265-400 kd glycoprotein. Obtained from the fatty globule of the human milk It is widely distributed in grand epithelia and patched in scaly type. Although at first it was thought that it was characteristic of breast carcinoma, we can detect it not only in adenocarcinomas of any origin but in transitional and epidermoid carcinomas (Zappa & Mousa, 2016). However, it can also be found in perineural and plasma cells as well as in a group with a high lymphatic degree of malignancy. In turn, it may lack the common leukocyte antigen.
In lung tissue, EMA is seen on the apical surface of the bronchiolar epithelium and glands seromucous like it is found in pneumocytes type I and II. Studies have found in adenocarcinomas and large cell carcinomas of the lung a diffuse and homogeneous positivity. In small cell carcinomas also found diffuse reactivity but weaker than in the previous ones (Anagnostou, & Brahmer, 2015). In carcinomas epidermoid, the expression of the EMA is heterogeneous that is predominant in keratinizing. Whether or not the expression has prognostic implications is something we are trying to know but, given that it can be detected in ritually processed tissue. It is a great help in the differential diagnosis of malignant tumours, including mesothelium, since it is negative or has a very weak reactivity.
In our experience, the expression of the EMA is directly related to the degree of tumour differentiation. Another antigen of importance is the so-called Ca detected by the monoclonal antibody Ca1, and which is constituted by a glycoprotein of 350-400 Kd (Kerr & Nicolson, 2016). When it is isolated, it is considered as a specific marker of malignancy (tumour associated antigen). However, subsequent sampling studies demonstrated that normal epithelial tissues. It also includes the bronchial and the type II pneumocytes, which also express it as well as the tumours that originate from them (Joshi et al. 2015). Interestingly, the prostate adenocarcinomas and gastrointestinal tumours lack such antigen.
Mesotheliomas, as was the case with EMA, are negative or very weakly positive.
Can use in the differential diagnosis. Also, it can be detected in plasma and used in the monitoring of the illness. There are many other antigens related to the previous one since they are related glycoproteins in a particular mode with cellular neoplastic transformation. Among them is the highlight of the Ca 15.3, recognized by the antibodies DF3 and 115D8. These antibodies emerge as a specific marker of breast carcinoma, Ca 125. It is s detected by the OC 125 antibody, also called celomic antigen and is expressed in serous carcinomas of the ovary and mesotheliomas (Joshi et al. 2015). Although it is also found in other types of carcinomas, ca 19.9 is another carbohydrate antigen associated with carcinoma. It is also expressed as B 72.3 that serves in discrimination between adenocarcinoma and mesothelioma.
The B1.1 antibody reacts with a 180 kd glycoprotein identical to the Carcinoembryonic antigen (CEA) and B 6.2 directed against a 90kd glycoprotein co-expressed with CEA. These are also useful in the diagnosis and follow-up of lung carcinomas. Tissue Polypeptide Antigen (TPA) is a molecule detected in most different types of lung carcinomas, as well as in many others from separate locations. It is instrumental in tracking the evolution of patients since it has a good sensitivity/specificity relationship (Joshi et al. 2015). Other antibodies and antigens have some specificity in the sense of constitute tumor-associated antigens such as LAM8 and SWA20 that identify membrane antigens present in 45% of small cell lung carcinomas. The MEI evident in adenocarcinomas, the Pulmonary Surfactant Apoprotein is recognized in bronchi-alveolar carcinomas, the Squamous Cell Carcinoma Antigen (SCC) present in a proportion of squamous cell carcinomas depending on its degree of differentiation and detection capacity in peripheral blood.