Smoking and alcohol abuse as the major risk factors. Viral causes has recently been taken under consideration as one of the risk factors. Viruses such as Epstein-Barr virus (EBV) (majorly involved in causing nasopharyngeal carcinoma) and human papilloma virus are included in this category. Chewing of betel nut ("Areca catechu") quid has been directly associated to cause oral cancers. It has also been stated under the FDA poisonous plant data base by the U.S Food and Drug Administration

An unbalanced diet, deficit in fruits and vegetables has shown to increase the risk of cancer.

When associated with the lung, it is typically a centrally located large cell cancer (non-small cell lung cancer or NSCLC). It often has a paraneoplastic syndrome causing ectopic production of parathyroid hormone-related protein (PTHrP), resulting in hypercalcemia, however paraneoplastic syndrome is more commonly associated with small cell lung cancer.

It is primarily due to smoking.

Between 250,000 and 1 million American women are diagnosed with CIN annually. Women can develop CIN at any age, however women generally develop it between the ages of 25 to 35.

Human papillomavirus infection (HPV) has been associated with SCC of the oropharynx, lung, fingers and anogenital region.

Laryngeal papillomatosis is caused by human papillomavirus (HPV), most frequently by types 6 and 11. The mode of transmission is found to differ depending on age. The disease is typically separated into two forms, juvenile and adult papillomatosis, based on whether it develops before or after 20 years of age. The juvenile form is generally transmitted through contact with a mother’s infected vaginal canal during childbirth. Less is known about transmission in the adult form of this disease, though oral sex has been implicated as a potential mode of transmission. However, it is uncertain whether oral sex would directly transmit the virus or activate the dormant virus that was transmitted at childbirth.

In general, physicians are unsure why only certain people who have been exposed to the HPV types implicated in the disease develop laryngeal papillomatosis. In the case of the juvenile form of the disease, the likelihood of a child born of an infected mother developing laryngeal papillomatosis is low (between 1 in 231 to 1 in 400), even if the mother’s infection is active. Risk factors for a higher likelihood of transmission at childbirth include the first birth, vaginal birth, and teenage mother.

It used to be thought that cases of CIN progressed through these stages toward cancer in a linear fashion.

However most CIN spontaneously regress. Left untreated, about 70% of CIN-1 will regress within one year, and 90% will regress within two years. About 50% of CIN 2 will regress within 2 years without treatment.

Progression to cervical carcinoma in situ (CIS) occurs in approximately 11% of CIN1 and 22% of CIN2. Progression to invasive cancer occurs in approximately 1% of CIN1, 5% in CIN2 and at least 12% in CIN3.

Progression to cancer typically takes 15 (3 to 40) years. Also, evidence suggests that cancer can occur without first detectably progressing through these stages and that a high grade intraepithelial neoplasia can occur without first existing as a lower grade.

It is thought that the higher risk HPV infections, have the ability to inactivate tumor suppressor genes such as the p53 gene and the RB gene, thus allowing the infected cells to grow unchecked and accumulate successive mutations, eventually leading to cancer.

Treatment does not affect the chances of getting pregnant but does increase the risk of second trimester miscarriages.

In a Meta-analysis study to conglomerate findings regarding 28 published papers including 158 patients presenting SNUC following up with patients for an average of 14 months showed that at the time of last follow up 25% of patients were alive with no evidence of the disease, 22.4% were alive with presence of the disease, and 52.6% were deceased due to the disease.

The evolution of laryngeal papillomatosis is highly unpredictable and is characterized by modulation of its severity and variable rate of progression across individuals. While instances of total recovery are observed, the condition is often persistent and lesions can reappear even after treatment. Factors that might affect the clinical course of the condition include: the HPV genotype, the age at onset, the elapsed time between the diagnosis and first treatment in addition to previous medical procedures. Other factors, albeit controversial, such as smoking or the presence gastroesophageal reflux disease might also play a role in the progression of the disease.

The papillomas can travel past the larynx and infect extralaryngeal sites. In more aggressive cases, infection of the lungs can occur with progressive airway obstruction. Although rare (less than 1% of people with laryngeal papillomatosis), transformation from a benign form to a malignant form is also observed. Death can result from these complications (morbidity rate is around 1-2%).

Around 75% of cases are caused by alcohol and tobacco use.

Tobacco smoke is one of the main risk factors for head and neck cancer and one of the most carcinogenic compounds in tobacco smoke is acrylonitrile. (See Tobacco smoking). Acrylonitrile appears to indirectly cause DNA damage by increasing oxidative stress, leading to increased levels of 8-oxo-2'-deoxyguanosine (8-oxo-dG) and formamidopyrimidine in DNA (see image). Both 8-oxo-dG and formamidopyrimidine are mutagenic. DNA glycosylase NEIL1 prevents mutagenesis by 8-oxo-dG and removes formamidopyrimidines from DNA.

However, cigarette smokers have a lifetime increased risk for head and neck cancers that is 5- to 25-fold increased over the general population.

The ex-smoker's risk for squamous cell cancer of the head and neck begins to approach the risk in the general population twenty years after smoking cessation. The high prevalence of tobacco and alcohol use worldwide and the high association of these cancers with these substances makes them ideal targets for enhanced cancer prevention.

Smokeless tobacco is cause of oral and pharyngeal cancers (oropharyngeal cancer). Cigar smoking is an important risk factor for oral cancers as well.

Other environmental carcinogens suspected of being potential causes of head and neck cancer include occupational exposures such as nickel refining, exposure to textile fibers, and woodworking. Use of marijuana, especially while younger, is linked to an increase in squamous-cell carcinoma cases while other studies suggest use is not shown to be associated with oral squamous cell carcinoma, or associated with decreased squamous cell carcinoma.

The etiology of florid cutaneous papillomatosis is unknown. It is likely directly induced by an underlying neoplasm secreting a growth factor. One candidate may be alpha-transforming growth factor, structurally related to epidermal growth factor, but antigenically distinct from it. The underlying cancer is most often gastric adenocarcinoma but also with breast cancer, bladder cancer, hepatobiliary cancer, ovarian cancer, uterine cancer, prostate cancer, lung cancer and cervical cancer. Other associated underlying malignancies include squamous cell carcinomas and lymphomas.

Immunotherapy with immune checkpoint inhibitors is being investigated in head and neck cancers.

Florid cutaneous papillomatosis is almost twice as common in men than in women, and is usually diagnosed in individuals aged 53–72 years (mean patient age, 58.5 years).

Sinonasal Undifferentiated Carcinoma (SNUC) is a rare and aggressive type of cancer originating in the epithelial layer of the nasal cavity or paranasal sinuses. It was first diagnosed in 1987. The aggressive nature of the cancer coupled with the advanced stage of disease upon presentation lead to a poor survival rate. Although the molecular nature of the mutation that causes SNUC is still poorly understood clinical treatment has shown that multimodality treatment has been the most successful option.

Urothelial carcinoma is a prototypical example of a malignancy arising from environmental carcinogenic influences. By far the most important cause is cigarette smoking, which contributes to approximately one-half of the disease burden. Chemical exposure, such as those sustained by workers in the petroleum industry, the manufacture of paints and pigments (e.g., aniline dyes), and agrochemicals are known to predispose one to urothelial cancer. Interestingly, risk is lowered by increased liquid consumption, presumably as a consequence of increased urine production and thus less "dwell time" on the urothelial surface. Conversely, risk is increased among long-haul truck drivers and others in whom long urine dwell-times are encountered. As with most epithelial cancers, physical irritation has been associated with increased risk of malignant transformation of the urothelium. Thus, urothelial carcinomas are more common in the context of chronic urinary stone disease, chronic catheterization (as in patients with paraplegia or multiple sclerosis), and chronic infections. Some particular examples are listed below:

1. Certain drugs, such as cyclophosphamide, via the metabolites acrolein and phenacetin, are known to predispose to TCC (the latter especially with respect to the upper urinary tract).

2. Radiation exposure

3. Somatic mutation, such as deletion of chromosome 9q, 9p, 11p, 17p, 13q, 14q and overexpression of RAS (oncogene) and epidermal growth factor receptor (EGFR).

Taken as a class, long-term survival rates in BAC tend to be higher than those of other forms of NSCLC. BAC generally carries a better prognosis than other forms of NSCLC, which can be partially attributed to localized presentation of the disease. Though other factors might play a role. Prognosis of BAC depends upon the histological subtype and extent at presentation but are generally same as other NSCLC.

Recent research has made it clear that nonmucinous and mucinous BACs are very different types of lung cancer. Mucinous BAC is much more likely to present with multiple unilateral tumors and/or in a unilateral or bilateral pneumonic form than nonmucinous BAC. The overall prognosis for patients with mucinous BAC is significantly worse than patients with nonmucinous BAC.

Although data are scarce, some studies suggest that survival rates are even lower in the mixed mucinous/non-mucinous variant than in the monophasic forms.

In non-mucinous BAC, neither Clara cell nor Type II pneumocyte differentiation appears to affect survival or prognosis.

Tonsillar carcinoma can be either HPV related or HPV unrelated. It is shown that cases which are HPV positive have a better prognosis than those with HPV negative oropharyngeal cancer.

Nasopharynx cancer as of 2010 resulted in 65,000 deaths globally up from 45,000 in 1990.

NPC is uncommon in the United States and most other nations, representing less than 1 case per 100,000 in most populations. but is extremely common in southern regions of China, particularly in Guangdong, accounting for 18% of all cancers in China. It is sometimes referred to as "Cantonese cancer" because it occurs in about 25 cases per 100,000 people in this region, 25 times higher than the rest of the world. It is also quite common in Taiwan. This could be due to the South East Asian diet which typically includes consumption of salted vegetables, fish and meat. While NPC is seen primarily in middle-aged persons in Asia, a high proportion of African cases appear in children. The cause of increased risk for NPC in these endemic regions is not clear. In low-risk populations, such as in the United States, a bimodal peak is observed. The first peak occurs in late adolescence/early adulthood (ages 15–24 years), followed by a second peak later in life (ages 65–79 years).

Accurate incidence statistics on MCACL are unavailable. It is a very rare tumor, with only a few dozen cases reported in the literature to date.

In the few cases described in the literature to date, the male-to-female ratio is approximately unity, and right lung lesions occurred twice as commonly as left lung lesions. Approximately 2/3 of cases have been associated with tobacco smoking. Cases have been reported in patients as young as 29.

EMECL is extremely rare, with only a handful of cases reported in the literature.

In the lung, two salivary gland-like carcinomas, mucoepidermoid carcinoma and adenoid cystic carcinoma, while extremely uncommon, occur far more often than does EMECL.

When BAC recurs after surgery, the recurrences are local in about three-quarters of cases, a rate higher than other forms of NSCLC, which tends to recur distantly.

Lymphoepithelioma-like carcinoma (LELC) is a medical term referring to a histological variant of malignant tumor arising from the uncontrolled mitosis of transformed cells originating in epithelial tissue (or in cells that display epithelial characteristics) that bear microscopic resemblance to lymphoepithelioma (nasopharyngeal carcinoma).

There is considerable variation in the classification of LELC—while it is perhaps most commonly considered a subtype of squamous cell carcinoma, it can also be classified as a form of large cell carcinoma (i.e. when occurring in the lung), and can be considered as a separate, unique entity.

In most anatomical sites, many cases are associated with the Epstein-Barr virus.

In the breast, the macroscopic, microscopic, epidemiologic, and prognostic features of LELC are very similar to "medullary carcinoma"; EBV status is one differentiator.

The median overall survival rate is about 50% in 5 years. Worse prognostic factors include the presence of residual tumor at the margin of the resection specimen (R+), invasion of the peritoneum and metastatic disease.

Head and neck cancers are malignant neoplasms that arise in the head and region which comprises nasal cavity, paranasal sinuses, oral cavity, salivary glands, pharynx, and larynx. Majority of head and neck cancers histologically belong to squamous cell type and hence they are categorized as Head and Neck Squamous Cell Carcinoma (abbreviated as HNSCC)[Forastiere AA, 2003]. HNSCC are the 6th most common cancers worldwide and 3rd most common cancers in developing world. They account for ~ 5% of all malignancies worldwide (Ferlay J, 2010) and 3% of all malignancies in the United States (Siegel R, 2014).

Risk factors include tobacco consumption (chewing or smoking), alcohol consumption, Epstein-Barr virus (EBV) infection, human papilloma virus (HPV; esp. HPV 16, 18) infection, betel nut chewing, wood dust exposures, consumption of certain salted fish and others (NCI Factsheet, 2013). EBV infection has been specifically associated with nasopharyngeal cancer. Reverse smoking was considered as a risk factor for oral cancer. Interestingly, "Cis-retinoic acid" (i.e. supplements of retinoic acid) intake may increase the risk of HNSCC in active smokers. Low consumption of fruits and vegetables was associated with higher incidence of HNSCC.

HNSCC classification: Based on the HPV infection status, head and neck cancers are classified into HPV-positive and HPV-negative categories. So far, this is the only available molecular classification. Majority (>50%) of oral cancers are HPV-positive in the U.S. HPV-positive oral cancers are widely prevalent in younger patients and are associated with multiple sexual partners and oral sexual practices. HPV-positive cancers have better prognosis, especially for nonsmokers as compared to HPV-negative cancers.

Staging and grading of HNSCC: HNSCC are classified according to the tumor-node-metastasis (TNM) system of American Joint Committee on cancer. TNM staging system for HNSCC are discussed else where.

Symptoms include lump or sore, sore throat, hoarse of voice, difficulty in swallowing etc (NCI Factsheet, 2013).

Treatment for HNSCC is predominantly based on the stage of the disease. Factors such as patient fitness, baseline swallow, airway functional status, and others are considered before determining the treatment plan. Standard of care for HNSCC includes one or combination of the following: surgery, radiation, chemotherapeutic agents such as Cisplatin, 5-Flurouracil (5-FU) etc. Molecularly targeted therapies were developed since the discovery of role of epidermal growth factor receptor (EGFR) signaling in HNSCC development, progression and prognosis. These targeted therapies include monoclonal antibodies (such as cetuximab, panitumumab etc.) and tyrosine kinase inhibitors (such as erlotinib, gefitinib, etc.). Among these EGFR-targeting agents, only cetuximab has been approved by FDA in 2006 for HNSCC treatment.

Ninety percent (MacMillan, 2015) of cases of head and neck cancer (cancer of the mouth, nasal cavity, nasopharynx, throat and associated structures) are due to squamous cell carcinoma. Symptoms may include a poorly healing mouth ulcer, a hoarse voice or other persistent problems in the area. Treatment is usually with surgery (which may be extensive) and radiotherapy. Risk factors include smoking, alcohol consumption and hematopoietic stem cell transplantation (Elad S, Zadik Y, Zeevi I, et al., 2010, pp. 1243–1244). In addition, recent studies show that about 25% of mouth and 35% of throat cancers are associated with HPV. The 5 year disease free survival rate for HPV positive cancer is significantly higher when appropriately treated with surgery, radiation and chemotherapy as compared to non-HPV positive cancer, substantiated by multiple studies including research conducted by Maura Gillison, "et al." of Johns Hopkins Sidney Kimmel Cancer Center.

Epithelial-myoepithelial carcinoma of the lung (EMECL) is a very rare histologic form of malignant epithelial neoplasm ("carcinoma") arising from lung tissue.

The average age at time of EIN diagnosis is approximately 52 years, compared to approximately 61 years for carcinoma. The timeframe and likelihood of EIN progression to cancer, however, is not constant amongst all women. Some cases of EIN are first detected as residual premalignant disease in women who already have carcinoma, whereas other EIN lesions disappear entirely and never lead to cancer. For this reason, treatment benefits and risks must be individualized for each patient under the guidance of an experienced physician.

Risk factors for development of EIN and the endometrioid type of endometrial carcinoma include exposure to estrogens without opposing progestins, obesity, diabetes, and rare hereditary conditions such as hereditary nonpolyposis colorectal cancer. Protective factors include use of combined oral contraceptive pills (low dose estrogen and progestin), and prior use of a contraceptive intrauterine device.