Level of mitoses in non-muscle invasive papillary urothelial carcinomas (pTa and pT1) at initial bladder biopsy is a simple and powerful predictor of clinical outcome: a multi-center study in South Korea

Quantitative nuclear grading: an objective, artificial intelligence-facilitated foundation for grading noninvasive papillary urothelial carcinoma

In non-muscle invasive bladder cancer, grade drives important treatment and management decisions. However, grading is complex, qualitative, and has considerable inter-and intra-observer variability. Previous literature showed that nuclear features quantitatively differ between bladder cancer grades, but these studies were limited in size and scope. Here, we measure morphometric features relevant to grading criteria and build simplified classification models that objectively distinguish between grades of non-invasive papillary urothelial carcinoma (NPUC). We analyzed 516 low-grade and 125 high-grade 1.0 mm diameter image samples from a cohort of 371 NPUC cases. All images underwent WHO/ISUP 2004 consensus pathologist grading at our institution that was subsequently validated by expert genitourinary pathologists from two additional institutions. Automated software segmented tissue regions and measured nuclear features of size, shape, and mitotic rate for millions of nuclei. We then analyzed differences between grades and constructed classification models which had accuracies up to 88% and areas under the curve as high as 0.94. Variation in the nuclear area was the best univariate discriminator and was prioritized, along with the mitotic index, in the top-performing classifiers. Adding shape-related variables improved accuracy further. These findings indicate that nuclear morphometry and automated mitotic figure counts can be used to objectively differentiate between grades of NPUC. Future efforts will adapt the workflow to whole slides and tune grading thresholds to best reflect time to recurrence and progression. Defining these essential quantitative elements of grading has the potential to revolutionize pathologic assessment and provide a starting point from which to improve the prognostic utility of grade.

Differential lysophosphatidylcholine acyltransferase 1 (LPCAT1) expression confers aggressiveness and independently predicts recurrence in bladder urothelial carcinomas

Bladder urothelial carcinomas are diverse in terms of biological behavior and this reflects the underlying complex metabolic and molecular pathways. Novel biomarkers that could assist in the management and outcome prediction of bladder urothelial carcinomas are eagerly needed. Recently, overexpression of lysophosphatidylcholine acyltransferase 1 (LPCAT1), a key enzyme in lipid metabolism, has been implicated in the evolvement of several tumors. In this study, LPCAT1 immunohistochemical expression was evaluated and statistically analyzed in 60 bladder urothelial carcinomas in relation to other clinicopathological parameters including the patient outcome. Twenty non-neoplastic bladder tissues served as a control group. Cases were followed up for a mean period of 9 months. LPCAT1 was expressed in all bladder urothelial carcinoma cases with two distinct patterns designated as high and low nuclear expression. Low LPCAT1 nuclear expression was detected in urothelial carcinoma cases as compared to the control group. Similarly, low nuclear expression of LPCAT1 was associated with high grade and invasive tumors and could independently predict tumor recurrence and short survival. In conclusion, LPCAT1 downregulation might be involved in bladder urothelial carcinoma tumorigenesis and could contribute to tumor aggressive phenotype. Retained LPCAT1 expression is an independent predictor of tumor recurrence and it represents a promising prognostic marker for patients' risk stratification.

Assessment of Histopathological Parameters Useful in the Diagnosis of Low Grade Non-Invasive Urothelial Carcinomas

Urothelial papillary lesions of urinary bladder are frequent lesions in medical practice and sometimes difficult to be histopathologically classified. In this study were included 179 urothelial papillary lesions, represented by low grade non-invasive urothelial carcinomas (LGNIUC), papillary urothelial neoplasms of low malignant potential (PUNLMP) and urothelial papillomas (UP), for which the architectural and cytological histopathological parameters were analyzed in order to determine their usefulness for the classification of lesions. For each parameter, an aggressivity score was set, the sum representing the composite histological score (CHS) for each case. The increase of urothelial thickness, the papillae fusion, the loss of cellular polarity, loss of basal cell palisading and absence of umbelliform cells were commonly associated with diffuse pattern in LGNIUC, were focal/absent in PUNLMP and absent in UP. The nuclear hypertrophy and hyperchromasia, the nucleoli presence and mitotic activity were specific for LGNIUC, rarely associated with PUNLMP and absent/low in UP. CHS values for the three categories of analyzed lesions were superior statistically significant in LGNIUC compared to PUNLMP and UP. The mitotic index and the thickness of cytological atypical epithelial layers support the parameters utility as reproducible criteria for the differentiation of papillary urothelial tumors.