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Byline: Shilpy. Jha, Prit. Mulgulwar, Mehar. Sharma, Suvendu. Purkait, Ashis. Pattnaik, Mukund. Sable Lipogenic differentiation in ependymoma is an infrequent occurrence with very few reported cases. The grading was done [...]

p16ink4a status is an independent predictor of survival in PC. There is a strong concordance between p16ink4a and HPV ISH results. Also, there is a significant association between HPV positivity and the histology with 100% of the warty, basaloid, and mixed warty-basaloid subtypes being positive for HPV. p53 is a predictor of nodal metastasis irrespective of p16ink4a status. Dual positive tumors (p16ink4a and p53 positive) have a significantly better outcome in comparison to dual negative tumors (both markers negative). Thus, p53 and p16ink4a immunohistochemistry should be performed at the baseline in all patients of PC. Background: Human papilloma virus (HPV) infection is implicated in a proportion of invasive squamous cell carcinoma of the penis (PC). A subset of PC involves dysregulation of the p53 pathway. HPV in situ hybridization (ISH) and p16ink4a positivity are surrogate markers for HPV infection, and p53 immunohistochemistry (IHC) denotes abnormality in the p53 pathway. There remains an ambiguity with regard to the contribution of both the pathways in the prognosis of PC. We sought to analyze the clinicopathologic characteristics of a cohort of Indian PC patients with respect to p16 ink4a and p53 expression. Patients and Methods: A cohort of 123 PC patients was studied for p16 ink4a and p53IHC and HPVISH. The results of these biomarkers were correlated with various clinicopathologic parameters. Results: p16 ink4a and HPV ISH were positive in 47% and 53% of the tumors, respectively. The propor tion of war ty, basaloid, or mixed war ty-basaloid tumor subtypes showed significant p16 ink4a positivity (P < .0001) compared to other subt ypes. Twent y-eight patients were dual negative (p53- /p16 ink4a -), 32 were dual positive (p53 + /p16 ink4a + ), 38 were p53 + /p16 ink4a -, and 25 were p53- /p16 ink4a + . In patients where p16 ink4a was negative, a p53-positive phenotype had a higher propensity for lymph node metastases (OR, 5.42; 95% CI, 1.75-16.80; P = .003). Similarly, p53 positivity dictates nodal involvement in the p16 ink4a - positive subset of tumors (OR, 5.00; 95% CI, 1.23-20.17; P = .024). On multivariate analyses, pathologic subtypes (warty, warty-basaloid, and basaloid) (P < .0001), p16 ink4a expression (P < .0001), and absence of nodal metastasis (P < .0001) were significant predictors of improved overall (OS) and cancer specific survival (CSS). In Kaplan-Meier analysis, the OS was significantly longer in patients with p16 ink4a + tumors (P < .0001), as was the CSS (P < .0001). Patients with dual positive tumors had a significantly higher OS (P < .001) and CSS (P = .012), in the entire cohort. In the node positive patients, dual positivity was associated with significantly higher OS (P < .0001); however, the median CSS for p53 + /p16 ink4a + tumors were not significantly different compared to p53- /p16 ink4a - tumors (P = .064), although there was a trend towards improved CSS. Conclusions: There is a strong concordance between p16 ink4a IHC and HPV ISH results. p16 ink4a status is an independent predictor of survival (OS and CSS) in our cohort of PCs. p53 is a predictor of nodal metastasis irrespective of p16 status. Dual positive tumors have a significantly better outcome in comparison to dual negative tumors. [ABSTRACT FROM AUTHOR]