Use of vimentin immunocytochemical staining for evaluation of atypical cells in voided urine samples

p53 expression in repair/reactive renal tubular cells: A potential pitfall leading to a false-positive diagnosis of urine cytology

Background

p53 immunostaining is routinely used as a surrogate marker for TP53 mutational status. In urine cytology, p53 immunocytochemistry is reportedly useful in detecting urothelial carcinoma cells as well as in improving the detection sensitivity and specificity. However, to the best of our knowledge, p53 expression in repair/reactive renal tubular cells (RRTCs) from urine cytologic specimens has not been assessed to date.

Methods

We evaluated the immunoexpression of p53 and homogentisate 1,2‐dioxygenase (HGD) antibody, a renal tubular cells marker, in RRTCs using voided urine and renal biopsy samples from 80 patients who were histologically diagnosed with glomerular disease.

Results

Repair/reactive renal tubular cells were detected in 68 (68/80, 85%) samples at a mean count of 141.1 cells per sample (range, 5–4220). Immunocytochemical analysis found p53‐positive RRTCs in all the samples (68/68, 100%) with an average p53 positivity rate of RRTCs per sample at 47.7% (range, 3.8%–96.5%). Of the 68 p53‐positive RRTC samples, 38 (55.9%) included cells that were HGD positive for cytoplasm. Similarly, renal biopsy analysis revealed p53‐positive RRTCs in all the specimens (68/68, 100%). All 68 (100%) cases showed RRTCs that were positive for both p53 and HGD.

Conclusion

To avoid false positives of p53 immunocytochemistry, cytologists must consider the fact that RRTCs from patients with glomerular disease are positive for p53.

Diffusive Ki67 and vimentin are associated with worse recurrence-free survival of upper tract urothelial carcinoma: A retrospective cohort study from bench to bedside

OBJECTIVES

This study aimed to determine the prognostic values of Ki67 and vimentin in upper tract urothelial carcinoma (UTUC) after extirpative surgery.

METHODS AND MATERIALS

Between 2014 and 2019, patients diagnosed with UTUC and receiving radical nephroureterectomy were included retrospectively. Nuclear MIB-1 clones and cytoplasmic VIM 3B4 clones were used to assess Ki67 and vimentin levels, respectively. A unified reading protocol was applied, and the expression level was read by a single pathologist. Receiver operating characteristic curves were utilized to determine the best threshold for Ki67 and vimentin regarding recurrence, and this level was set as the diffusive level. The outcome of recurrence-free survival (RFS) was analyzed via a Cox regression model with univariable and multivariable approaches. Survival outcomes were analyzed via Kaplan-Meier (KM) curves.

RESULTS

A total of 247 patients were included, and the mean follow-up was 29.90 ± 6.80 months. Diffusive thresholds were 17.5% for both Ki67 and vimentin. Under multivariable Cox regression, diffusive Ki67 (hazard ratio: 4.20 [2.39-7.37], P < 0.001) and diffusive vimentin (hazard ratio: 5.34 [3.10-9.22], P < 0.001) were significant prognostic indicators of worse RFS. Diffusive Ki67 was accompanied by diffusive vimentin (chi square with Yates' correction, P = 0.015), and vice versa. In the KM curve, there was no difference between diffusive Ki67/nondiffusive vimentin and nondiffusive Ki67/diffusive vimentin (log-rank test, P = 0.073). Significant differences (log-rank test, P < 0.001) were seen in different combinations of diffusive Ki67/vimentin (Mean RFS: 19.76 [18.56-20.96] months), only one diffusive in Ki67 or vimentin (Mean RFS: 22.94 [21.88-24.00] months), and nondiffusive Ki67/vimentin (Mean RFS: 32.96 [32.43-33.50] months).

CONCLUSIONS

Diffusive Ki67 and vimentin were related to each other, and they exerted equivalent and synergic effects on predicting worse RFS in UTUC.