Exploring the histogenesis of STK11 adnexal tumour using electron microscopy.

STK11 adnexal tumour is a recently described female genital tract tumour, usually identified in a paratubal location, often associated with Peutz-Jeghers syndrome (PJS) and with STK11 gene alterations identified in most of the cases. Morphologically, this tumour is composed of cells arranged in a variety of patterns, including cords, trabeculae, tubules and cystic and acinar structures. The cells are only moderately pleomorphic and mitotic activity is variable. As tumour cells express epithelial, sex cord stromal and mesothelial markers, STK11 adnexal tumour may be of sex cord stromal, epithelial or mesothelial origin; a Wolffian origin has also been suggested. We report the ultrastructural features of two STK11 adnexal tumours and compare their ultrastructural features with those of other sex cord stromal tumours, a granulosa cell tumour cell line, as well as the known ultrastructural features of epithelial, mesothelial and Wolffian cells. On ultrastructural examination, two STK11 adnexal tumours showed an admixture of elongated cells with regular elongated nuclei and polygonal cells with nuclei showing markedly irregular outlines and prominent nucleoli. Extracellular collagen fibres were identified. These are common ultrastructural features of sex cord stromal tumours, principally sex cord tumour with annular tubules; no ultrastructural features of epithelial, mesothelial or Wolffian cells were found. These findings in conjunction with the shared clinical and genetic association with PJS and shared molecular changes in STK11 gene suggest that STK11 adnexal tumour represents a poorly differentiated sex cord tumour.

The Prognostic Impact of Tumor Border Configuration, Tumor Budding and Tumor Stroma Ratio in Colorectal Carcinoma.

OBJECTIVE: Tumor border configuration, tumor budding and tumor stroma ratio are reliable histopathological parameters that play a central role in the invasion-metastasis cascade. This study aimed to investigate the prognostic impact of these parameters and a new combined score in colorectal cancer. MATERIAL AND METHOD: A cohort of 103 colorectal cancer surgical specimens was retrospectively evaluated for tumor border configuration, tumor budding and tumor stroma ratio using H&E sections. A combined risk score was then constructed to divide cases into low risk-tumors and high risk-tumors. RESULTS: Infiltrating tumor border, high tumor budding, low tumor stroma ratio and high combined risk score were associated with positive lymph node involvement, presence of metastasis, high tumor grade, lymphovascular invasion, poor overall survival and short recurrence-free survival. Infiltrating tumor border, high tumor budding and high combined risk score were associated with advanced T stage. High tumor budding, and low tumor stroma ratio were associated with perineural invasion. Infiltrating tumor border was associated with increased tumor size and conventional adenocarcinoma, high tumor budding and low tumor stroma ratio. Low tumor stroma ratio was associated with high tumor budding. On multivariate survival analysis, tumor stroma ratio was found to be an independent predictor for overall survival and recurrence-free survival. CONCLUSION: Tumor border configuration, tumor budding, tumor stroma ratio and the newly constructed combined risk score are potential predictors of outcome in colorectal cancer patients, suggesting that their incorporation in the routine histopathological evaluation could be useful in determining the prognosis of colorectal cancer cases.

The role and relationship between programmed death ligand 1 and cytotoxic T lymphocyte-associated antigen-4 immunohistochemical expression in colorectal carcinoma patients: an impact on outcome.

BACKGROUND: Globally, colorectal carcinoma (CRC) is the third most common cancer diagnosed in both men and women. Programmed death ligand 1 (PD-L1) and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) are immune checkpoints that induce tumour immune escape. AIM: This study aimed to evaluate the immunohistochemical expression of PD-L1 and CTLA-4 in CRC and their relationship with clinicopathological parameters and survival data. RESULT: This study included 103 CRC, 22 adenoma and 21 non-neoplastic specimens. High PD-L1 epithelial expression was in favour of CRC and high-grade dysplastic adenoma compared to normal specimens. High PD-L1 epithelial expression was associated with larger sized tumours, perforation, advanced T stage, infiltrative tumour border configuration (TBC), high tumour budding (TB) score, low tumour-stroma ratio (TSR) and absence of peritumoural lymphocytes. High PD-L1+ tumour infiltrating lymphocytes (TILs) showed an association with absence of perforation, early T stage, pushing TBC, lower TB score, high TSR and presence of peritumoural lymphocytes. High epithelial CTLA-4 expression was in favour of adenocarcinoma, high-grade dysplastic adenoma and low-grade dysplastic adenoma compared to normal specimens. High CTLA-4 epithelial score showed an association with positive lymph nodes (LNs), presence of an infiltrative TBC and absence of peritumoural lymphocytes. Low CTLA-4+ TILs showed a significant association with advanced tumour stage and increased number of positive LNs. Prolonged survival was associated with low epithelial PD-L1 and CTLA-4, high PD-L1+ TILs and high CTLA-4+ TILs. By multivariate Cox regression analysis, PD-L1+ TILs immunoreactivity score (p = 0.020) and CTLA-4+ TILs H. score (p = 0.036) were independent prognostic factors affecting overall survival among the other prognostic factors. CONCLUSION: PD-L1 and CTLA-4 expression by tumour cells could cooperate with each other in enhancing progression of CRC leading to poor patient outcome, while their expression by TILs could stand against tumour progression.