Relevance of Partial p16 Immunostaining in Oral Squamous Cell Carcinoma and Co- Relation with HPV DNA Status.

INTRODUCTION: Immunostaining criteria for p16 positivity in oropharyngeal squamous cell carcinoma have been laid down by College of American Pathologists (CAP) and the American Society of Clinical Oncology (ASCO). The staining should be of moderate to strong intensity seen in 70 percent of the tumor cells. Recent studies have pointed out that a small minority of cases are missed using p16 as the surrogate marker at above mentioned cut off. By convention the same criteria have been used for oral squamous cell carcinoma. MATERIAL AND METHODS: The authors revisited the results of their previous study where immunohistochemistry for p16 was found to be positive by AJCC criteria in 139 out of 800 cases of oral squamous cell carcinoma. For this study, all the p16 immunonegative cases (by AJCC criteria) were analysed again for partial staining patterns, defined for this study as cases with 50-75% cells showing 2+/3+ intensity of nuclear p16 immunostaining and for basal predominant pattern of immunostaining. These cases were subjected to HPV DNA PCR. RESULTS: Out of the 661/800 cases found to be negative for p16 immunohistochemistry, a total of 34/800(4.25%) showed partial staining based on the criterion of 50-75% cells showing p16 immunostaining intensity of 2/3+.The basal predominant pattern of immunostaining for p16 was seen in 43/800 (5.38%) cases. When these cases were subjected to HPV DNA analysis, 11/34 (32.35%) of the cases showing partial staining and 02/43 (4.7%) of the cases showing basal predominant pattern of p16 immunostaining were found to be HPV-DNA positive. CONCLUSION: The inclusion of partial immunostaining patterns of p16 in HPV analysis of oral squamous cell carcinoma can improve our understanding of HPV driven oral squamous cell carcinoma.

Clinico-pathological features in fatal Covid-19 Infection: A Preliminary Experience of a Tertiary Care Centre in North India using Post-Mortem Minimally Invasive Tissue Biopsies

BackgroundThe Covid-19 pandemic began in China in December 2019. India is the second most affected country, as of November 2020 with more than 8.5million cases. Covid-19 infection primarily involves the lung with severity of illness varying from influenza-like illness to acute respiratory distress syndrome. Other organs have also found to be variably affected. Studies evaluating the histopathological changes of Covid-19 are critical in providing a better understanding of the disease pathophysiology and guiding treatment. Minimally invasive biopsy techniques (MITS/B) provide an easy and suitable alternative to complete autopsies. In this prospective single center study we present the histopathological examination of 37 patients who died with complications of Covid-19. MethodsThis was an observational study conducted in the Intensive Care Unit of JPN Trauma Centre AIIMS. A total of 37 patients who died of Covid-19 were enrolled in the study. Post-mortem percutaneous biopsies were taken by the help of surface landmarking/ultrasonography guidance from lung, heart, liver, and kidneys; after obtaining ethical consent. The biopsy samples were then stained with haematoxylin and eosin stain. Immunohistochemistry (IHC) was performed using CD61 and CD163 in all lung cores. SARS-CoV-2 virus was detected using IHC with primary antibodies in selected samples. Details regarding demographics, clinical parameters, hospital course, treatment details, and laboratory investigations were also collected for clinical correlation. ResultsA total of 37 patients underwent post-mortem minimally invasive tissue sampling. Mean age of the patients was 48.7years and 59.5% of them were males. Respiratory failure was the most common complication seen in 97.3%. Lung histopathology showed acute lung injury and diffuse alveolar damage in 78% patients. Associated bronchopneumonia was seen in 37.5% patients and scattered microthrombi were visualised in 21% patients. Immunostaining with CD61 and CD163 highlighted megakaryocytes, and increased macrophages in all samples. Immunopositivity for SARS-CoV-2 was observed in Type II pneumocytes. Acute tubular injury with epithelial vacuolization was seen in 46% of the renal biopsies but none of them showed evidence of microvascular thrombosis. 71% of the liver tissue cores showed evidence of Kupfer cell hyperplasia. 27.5% had evidence of submassive hepatic necrosis and 14% had features of acute on chronic liver failure. All the heart biopsies showed non-specific features such as hypertrophy with nucleomegaly with no evidence of myocardial necrosis in any of the samples. ConclusionsThe most common finding in this cohort is the diffuse alveolar damage with demonstration of SARS-CoV-2 protein in the acute phase of DAD. Microvascular thrombi were rarely identified in the lung, liver and kidney. Substantial hepatocyte necrosis, hepatocyte degeneration, Kupffer cell hypertrophy, micro, and macrovesicular steatosis unrelated to microvascular thrombi suggests that liver might be a primary target of Covid-19. This study highlights the importance of MITS/B in better understanding the pathological changes associated with Covid-19.