Publications by authors named "Mahir A Petkar"

The lack of multi-omics cancer datasets with extensive follow-up information hinders the identification of accurate biomarkers of clinical outcome. In this cohort study, we performed comprehensive genomic analyses on fresh-frozen samples from 348 patients affected by primary colon cancer, encompassing RNA, whole-exome, deep T cell receptor and 16S bacterial rRNA gene sequencing on tumor and matched healthy colon tissue, complemented with tumor whole-genome sequencing for further microbiome characterization. A type 1 helper T cell, cytotoxic, gene expression signature, called Immunologic Constant of Rejection, captured the presence of clonally expanded, tumor-enriched T cell clones and outperformed conventional prognostic molecular biomarkers, such as the consensus molecular subtype and the microsatellite instability classifications.

View Article and Find Full Text PDF

Granulosa cell tumor (GCT) is a unique form of sex cord tumor that is mostly unilateral and of low-grade malignancy. Most GCT recurrence is with pelvic or peritoneal dissemination. Liver metastasis is rarely reported.

View Article and Find Full Text PDF

Angiosarcomas represent highly-aggressive malignant lesions of the endothelial cells of blood vessels, affecting mostly the elderly population, and usually located in the scalp or face. As cutaneous angiosarcomas often metastasize to the lung, they can manifest in various forms. We report a case of a 77-year-old male who presented after a posttraumatic blunt scalp lump that was initially diagnosed as infected subgaleal hematoma.

View Article and Find Full Text PDF

Invasive aspergillosis is commonly encountered in immunosuppressed patients either primarily through direct inoculation or secondary from blood dissemination. This report describes a case of 53 years old immunocompromised female patient who was diagnosed with frontotemporal anaplastic astrocytoma and developed nasal skin lesion turned to be invasive cutaneous aspergillosis.

View Article and Find Full Text PDF

Rett syndrome (RTT) is a progressive neurological disorder, affecting females with mutations in the X-linked gene methyl-CpG-binding protein 2 (MECP2). While MECP2 has been implicated in cancers of the breast, colon, and prostrate, cancer in patients with RTT is rare. We present a case of malignant melanoma in a patient with RTT, which additionally, displayed hitherto undescribed nuclear features, resembling herpes simplex virus cytopathic effects.

View Article and Find Full Text PDF

Background: We describe a case of a young male with a history of appendectomy one year ago, who developed symptoms of stump appendicitis, and after removing this stump, histopathology showed low grade neoplasm. . Stump appendicitis is an uncommon complication after appendectomy and may lead to serious complications.

View Article and Find Full Text PDF

Background: Cytotoxic CD8 T cell-mediated response is the most important arm of adaptive immunity, which dictates the capacity of the host immune response in eradicating tumor cells. Due to tumor intrinsic and/or extrinsic factors, the density and function of CD8 tumor-infiltrating lymphocytes (TILs) could be compromised, leading to poor prognosis and survival.

Methods: Using RNA-Seq, transcriptomes of sorted CD3CD8 TILs from treatment-naïve colorectal cancer (CRC) patients at advanced stages (III and IV) were compared with those from patients with early stages (I and II).

View Article and Find Full Text PDF

Despite recent advances in colorectal cancer (CRC) treatment, a large proportion of patients show limited responses to therapies, especially in advanced stages. There is an urgent need to identify prognostic biomarkers and/or therapeutic targets in advanced stages, aiming to improve the efficacy of current treatments. We aimed to determine prognostic biomarkers in tumor tissue and circulation of CRC patients, with a special focus on T cell exhaustion markers.

View Article and Find Full Text PDF

Introduction: A mass in the salivary gland region often presents a diagnostic challenge with regard to its site of origin (salivary versus nonsalivary), benign or malignant nature, and tissue-specific diagnosis. The present study describes the utility of fine-needle aspiration (FNA) cytology in the diagnosis of these lesions.

Subjects And Methods: Over a 6-year period (January 1994 to December 1999), 712 patients aged between 6 months and 91 years (median, 37 years) were subjected to FNA of swellings in their salivary gland regions.

View Article and Find Full Text PDF