Papilloma: A circumscribed benign epithelial tumor projecting from the surrounding surface; more precisely, a benign epithelial neoplasm consisting of villous or arborescent outgrowths of fibrovascular stroma covered by neoplastic cells. (Stedman, 25th ed)Papilloma, Inverted: A mucosal tumor of the urinary bladder or nasal cavity in which proliferating epithelium is invaginated beneath the surface and is more smoothly rounded than in other papillomas. (Stedman, 25th ed)Papilloma, Intraductal: A small, often impalpable benign papilloma arising in a lactiferous duct and frequently causing bleeding from the nipple. (Stedman, 25th ed)Papilloma, Choroid Plexus: A usually benign neoplasm that arises from the cuboidal epithelium of the choroid plexus and takes the form of an enlarged CHOROID PLEXUS, which may be associated with oversecretion of CSF. The tumor usually presents in the first decade of life with signs of increased intracranial pressure including HEADACHES; ATAXIA; DIPLOPIA; and alterations of mental status. In children it is most common in the lateral ventricles and in adults it tends to arise in the fourth ventricle. Malignant transformation to choroid plexus carcinomas may rarely occur. (Adams et al., Principles of Neurology, 6th ed, p667; DeVita et al., Cancer: Principles and Practice of Oncology, 5th ed, p2072)9,10-Dimethyl-1,2-benzanthracene: 7,12-Dimethylbenzanthracene. Polycyclic aromatic hydrocarbon found in tobacco smoke that is a potent carcinogen.Skin Neoplasms: Tumors or cancer of the SKIN.Papillomaviridae: A family of small, non-enveloped DNA viruses infecting birds and most mammals, especially humans. They are grouped into multiple genera, but the viruses are highly host-species specific and tissue-restricted. They are commonly divided into hundreds of papillomavirus "types", each with specific gene function and gene control regions, despite sequence homology. Human papillomaviruses are found in the genera ALPHAPAPILLOMAVIRUS; BETAPAPILLOMAVIRUS; GAMMAPAPILLOMAVIRUS; and MUPAPILLOMAVIRUS.Cottontail rabbit papillomavirus: The type species of KAPPAPAPILLOMAVIRUS. It is reported to occur naturally in cottontail rabbits in North America.Human papillomavirus 11: A type of ALPHAPAPILLOMAVIRUS causing recurrent respiratory PAPILLOMATOSIS; GENITAL WARTS; and other neoplasms.Papillomavirus Infections: Neoplasms of the skin and mucous membranes caused by papillomaviruses. They are usually benign but some have a high risk for malignant progression.Warts: Benign epidermal proliferations or tumors; some are viral in origin.Choroid Plexus Neoplasms: Benign or malignant tumors which arise from the choroid plexus of the ventricles of the brain. Papillomas (see PAPILLOMA, CHOROID PLEXUS) and carcinomas are the most common histologic subtypes, and tend to seed throughout the ventricular and subarachnoid spaces. Clinical features include headaches, ataxia and alterations of consciousness, primarily resulting from associated HYDROCEPHALUS. (From Devita et al., Cancer: Principles and Practice of Oncology, 5th ed, p2072; J Neurosurg 1998 Mar;88(3):521-8)Nose Neoplasms: Tumors or cancer of the NOSE.Tumor Virus Infections: Infections produced by oncogenic viruses. The infections caused by DNA viruses are less numerous but more diverse than those caused by the RNA oncogenic viruses.Mice, Inbred SENCAR: Mice selectively bred for hypersusceptibility to two-stage chemical skin carcinogenesis. They are also hypersusceptible to UV radiation tumorigenesis with single high-dose, but not chronic low-dose, exposures. SENCAR (SENsitive to CARcinogenesis) mice are used in research as an animal model for tumor production.Carcinogens: Substances that increase the risk of NEOPLASMS in humans or animals. Both genotoxic chemicals, which affect DNA directly, and nongenotoxic chemicals, which induce neoplasms by other mechanism, are included.Paranasal Sinus Neoplasms: Tumors or cancer of the PARANASAL SINUSES.Cocarcinogenesis: The combination of two or more different factors in the production of cancer.Laryngeal Neoplasms: Cancers or tumors of the LARYNX or any of its parts: the GLOTTIS; EPIGLOTTIS; LARYNGEAL CARTILAGES; LARYNGEAL MUSCLES; and VOCAL CORDS.Bovine papillomavirus 4: A type of XIPAPILLOMAVIRUS causing alimentary carcinoma in cattle. It is related to Bovine papillomavirus 3.Bovine papillomavirus 1: A species of DELTAPAPILLOMAVIRUS infecting cattle.Carcinoma, Squamous Cell: A carcinoma derived from stratified SQUAMOUS EPITHELIAL CELLS. It may also occur in sites where glandular or columnar epithelium is normally present. (From Stedman, 25th ed)Conjunctival Neoplasms: Tumors or cancer of the CONJUNCTIVA.Neoplasm Regression, Spontaneous: Disappearance of a neoplasm or neoplastic state without the intervention of therapy.Oncogene Proteins, Viral: Products of viral oncogenes, most commonly retroviral oncogenes. They usually have transforming and often protein kinase activities.Tetradecanoylphorbol Acetate: A phorbol ester found in CROTON OIL with very effective tumor promoting activity. It stimulates the synthesis of both DNA and RNA.Genes, ras: Family of retrovirus-associated DNA sequences (ras) originally isolated from Harvey (H-ras, Ha-ras, rasH) and Kirsten (K-ras, Ki-ras, rasK) murine sarcoma viruses. Ras genes are widely conserved among animal species and sequences corresponding to both H-ras and K-ras genes have been detected in human, avian, murine, and non-vertebrate genomes. The closely related N-ras gene has been detected in human neuroblastoma and sarcoma cell lines. All genes of the family have a similar exon-intron structure and each encodes a p21 protein.Uterine Cervical Neoplasms: Tumors or cancer of the UTERINE CERVIX.DNA, Viral: Deoxyribonucleic acid that makes up the genetic material of viruses.Human papillomavirus 16: A type of ALPHAPAPILLOMAVIRUS especially associated with malignant tumors of the CERVIX and the RESPIRATORY MUCOSA.Respiratory Tract NeoplasmsEpidermis: The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of EPITHELIUM: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis).Cerebral Ventricle Neoplasms: Neoplasms located in the brain ventricles, including the two lateral, the third, and the fourth ventricle. Ventricular tumors may be primary (e.g., CHOROID PLEXUS NEOPLASMS and GLIOMA, SUBEPENDYMAL), metastasize from distant organs, or occur as extensions of locally invasive tumors from adjacent brain structures.Skin: The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.Keratoacanthoma: A benign, non-neoplastic, usually self-limiting epithelial lesion closely resembling squamous cell carcinoma clinically and histopathologically. It occurs in solitary, multiple, and eruptive forms. The solitary and multiple forms occur on sunlight exposed areas and are identical histologically; they affect primarily white males. The eruptive form usually involves both sexes and appears as a generalized papular eruption.Benzoyl Peroxide: A peroxide derivative that has been used topically for BURNS and as a dermatologic agent in the treatment of ACNE and POISON IVY DERMATITIS. It is used also as a bleach in the food industry.Cell Transformation, Neoplastic: Cell changes manifested by escape from control mechanisms, increased growth potential, alterations in the cell surface, karyotypic abnormalities, morphological and biochemical deviations from the norm, and other attributes conferring the ability to invade, metastasize, and kill.Keratinocytes: Epidermal cells which synthesize keratin and undergo characteristic changes as they move upward from the basal layers of the epidermis to the cornified (horny) layer of the skin. Successive stages of differentiation of the keratinocytes forming the epidermal layers are basal cell, spinous or prickle cell, and the granular cell.Papillomavirus E7 Proteins: ONCOGENE PROTEINS from papillomavirus that deregulate the CELL CYCLE of infected cells and lead to NEOPLASTIC CELL TRANSFORMATION. Papillomavirus E7 proteins have been shown to interact with various regulators of the cell cycle including RETINOBLASTOMA PROTEIN and certain cyclin-dependent kinase inhibitors.Neoplasms, Experimental: Experimentally induced new abnormal growth of TISSUES in animals to provide models for studying human neoplasms.Keratins: A class of fibrous proteins or scleroproteins that represents the principal constituent of EPIDERMIS; HAIR; NAILS; horny tissues, and the organic matrix of tooth ENAMEL. Two major conformational groups have been characterized, alpha-keratin, whose peptide backbone forms a coiled-coil alpha helical structure consisting of TYPE I KERATIN and a TYPE II KERATIN, and beta-keratin, whose backbone forms a zigzag or pleated sheet structure. alpha-Keratins have been classified into at least 20 subtypes. In addition multiple isoforms of subtypes have been found which may be due to GENE DUPLICATION.Carcinoma: A malignant neoplasm made up of epithelial cells tending to infiltrate the surrounding tissues and give rise to metastases. It is a histological type of neoplasm but is often wrongly used as a synonym for "cancer." (From Dorland, 27th ed)Tracheal NeoplasmsHyperplasia: An increase in the number of cells in a tissue or organ without tumor formation. It differs from HYPERTROPHY, which is an increase in bulk without an increase in the number of cells.Maxillary Sinus Neoplasms: Tumors or cancer of the MAXILLARY SINUS. They represent the majority of paranasal neoplasms.Carcinogenicity Tests: Tests to experimentally measure the tumor-producing/cancer cell-producing potency of an agent by administering the agent (e.g., benzanthracenes) and observing the quantity of tumors or the cell transformation developed over a given period of time. The carcinogenicity value is usually measured as milligrams of agent administered per tumor developed. Though this test differs from the DNA-repair and bacterial microsome MUTAGENICITY TESTS, researchers often attempt to correlate the finding of carcinogenicity values and mutagenicity values.Nipples: The conic organs which usually give outlet to milk from the mammary glands.Precancerous Conditions: Pathological processes that tend eventually to become malignant. (From Dorland, 27th ed)Larynx: A tubular organ of VOICE production. It is located in the anterior neck, superior to the TRACHEA and inferior to the tongue and HYOID BONE.Papillomavirus Vaccines: Vaccines or candidate vaccines used to prevent PAPILLOMAVIRUS INFECTIONS. Human vaccines are intended to reduce the incidence of UTERINE CERVICAL NEOPLASMS, so they are sometimes considered a type of CANCER VACCINES. They are often composed of CAPSID PROTEINS, especially L1 protein, from various types of ALPHAPAPILLOMAVIRUS.Condylomata Acuminata: Sexually transmitted form of anogenital warty growth caused by the human papillomaviruses.Parrots: BIRDS of the large family Psittacidae, widely distributed in tropical regions and having a distinctive stout, curved hooked bill. The family includes LOVEBIRDS; AMAZON PARROTS; conures; PARAKEETS; and many other kinds of parrots.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.Croton Oil: Viscous, nauseating oil obtained from the shrub Croton tiglium (Euphorbaceae). It is a vesicant and skin irritant used as pharmacologic standard for skin inflammation and allergy and causes skin cancer. It was formerly used as an emetic and cathartic with frequent mortality.Endoscopy: Procedures of applying ENDOSCOPES for disease diagnosis and treatment. Endoscopy involves passing an optical instrument through a small incision in the skin i.e., percutaneous; or through a natural orifice and along natural body pathways such as the digestive tract; and/or through an incision in the wall of a tubular structure or organ, i.e. transluminal, to examine or perform surgery on the interior parts of the body.Alphapapillomavirus: A genus of DNA viruses in the family PAPILLOMAVIRIDAE. They preferentially infect the anogenital and ORAL MUCOSA in humans and primates, causing both malignant and benign neoplasms. Cutaneous lesions are also seen.Etretinate: An oral retinoid used in the treatment of keratotic genodermatosis, lichen planus, and psoriasis. Beneficial effects have also been claimed in the prophylaxis of epithelial neoplasia. The compound may be teratogenic.