Cytokeratin 7 (CK7) is a protein made by epithelial cells in the thyroid gland, lungs, thymus, female reproductive organs, upper digestive tract, and head and neck. This type of protein is also made by most benign (noncancerous) and malignant (cancerous) tumours that start in these organ systems. After CK7 is made, it is held in the cytoplasm (body) of the cell. It is known that breast cancer may express p16 positivity from 10-55% [ 10 ]. There are no data in metaplastic breast cancer for p16 positivity to our knowledge. Metaplastic breast cancer is an aggressive subtype of breast cancer and may be frequently be axillary node negative. According to Hennessy although mostly triple negative they resemble A surrogate marker of high-risk HPV, p16 has the ability to help discriminate and identify subtle dysplasias/malignancies in often fragmented, miniscule cervical biopsy specimens. This immunohistochemical (IHC) stain has been an invaluable tool for pathologists over many years. More recently, however, the use of p16 has been incorporated into p16 Ink4a is a protein involved in regulation of the cell cycle. Currently, p16 Ink4a is considered a tumor suppressor protein because of its physiological role and downregulated expression in a The .gov means it's official. Federal government websites often end in .gov or .mil. (p16 score = 0, i.e. no tumor cells showed any staining for p16). Of the two Type 1 biopsies (22%) with some p16 positive IHC staining, one was 1+ (1-25% of tumor cells stained positive for p16) and the other was 2+ (26-50% of tumor cells stained Some people can have elevated levels of p16 but test negative for HPV and vice versa. This is known as discordant cancer. The 5-year survival for people who test positive for HPV and p16 is 81%, for discordant cancer it is 53 - 55%, and 40% for those who test negative for p16 and HPV. Determinants of survival Cytokeratin 5/6 is a positive marker for malignant pleural mesothelioma, found in more than three-fourths of cases. It is also found in certain types of lung cancers and breast cancers. Pathologists use cytokeratin 5/6 to stain cancer tissue samples. Pleural mesothelioma is often misdiagnosed as lung cancer. It is currently not clear whether p16-negative -IN2 lesions consistently behave like precancer (with progression) or like transient HPV-induced lesions (with regression). Guedes et al. found no significant difference in regression between p16-positive and p16-negative CIN2 lesions, further undermining p16 positivity as a threshold for treatment 26. Mean age of the patients involved in the study was 48.9 years. Most of the patients presented at stage T2 with a high mean ki67 index i.e. 46.9%. 42.7% of cases had nodal metastasis. Seventy-one percent (98 cases) of cases showed positive p16 expression, whereas 24.8% (34 cases) were negative and 3.6% (5 cases) showed focal positive p16 In summary, p16 positive, HPV negative oropharyngeal SCC has survival comparable to p16 positive, HPV positive SCC and statistically significantly better than p16 negative, HPV negative SCC. p16 identifies the largest cohort (~ 80%) of "good prognosis" oropharyngeal SCC. wSRb.