Prognostic value of Ki67 in localized prostate carcinoma: a multi-institutional study of >1000 prostatectomies.

BACKGROUND: Expanding interest in and use of active surveillance for early state prostate cancer (PC) has increased need for prognostic biomarkers. Using a multi-institutional tissue microarray resource including over 1000 radical prostatectomy samples, we sought to correlate Ki67 expression captured by an automated image analysis system with clinicopathological features and validate its utility as a clinical grade test in predicting cancer-specific outcomes. METHODS: After immunostaining, the Ki67 proliferation index (PI) of tumor areas of each core (three cancer cores/case) was analyzed using a nuclear quantification algorithm (Aperio). We assessed whether Ki67 PI was associated with clinicopathological factors and recurrence-free survival (RFS) including biochemical recurrence, metastasis or PC death (7-year median follow-up). RESULTS: In 1004 PCs (∼4000 tissue cores) Ki67 PI showed significantly higher inter-tumor (0.68) than intra-tumor variation (0.39). Ki67 PI was associated with stage (P<0.0001), seminal vesicle invasion (SVI, P=0.02), extracapsular extension (ECE, P<0.0001) and Gleason score (GS, P<0.0001). Ki67 PI as a continuous variable significantly correlated with recurrence-free, overall and disease-specific survival by multivariable Cox proportional hazard model (hazards ratio (HR)=1.04-1.1, P=0.02-0.0008). High Ki67 score (defined as ⩾5%) was significantly associated with worse RFS (HR=1.47, P=0.0007) and worse overall survival (HR=2.03, P=0.03). CONCLUSIONS: In localized PC treated by radical prostatectomy, higher Ki67 PI assessed using a clinical grade automated algorithm is strongly associated with a higher GS, stage, SVI and ECE and greater probability of recurrence.

Low-density lipoprotein receptor-related protein 5 (LRP5) mediates the prostate cancer-induced formation of new bone.

The tendency of prostate cancer to produce osteoblastic bone metastases suggests that cancer cells and osteoblasts interact in ways that contribute to cancer progression. To identify factors that mediate these interactions, we compared gene expression patterns between two bone-derived prostate cancer cell lines that produce osteoblastic (MDA PCa 2b) or osteolytic lesions (PC-3). Both cell lines expressed Wnt ligands, including WNT7b, a canonical Wnt implicated in osteogenesis. PC-3 cells expressed 50 times more Dickkopf-1 (DKK1), an inhibitor of Wnt pathways, than did MDA PCa 2b cells. Evaluation of the functional role of these factors (in cocultures of prostate cancer cells with primary mouse osteoblasts (PMOs) or in bone organ cultures) showed that MDA PCa 2b cells activated Wnt canonical signaling in PMOs and that DKK1 blocked osteoblast proliferation and new bone formation induced by MDA PCa 2b cells. MDA PCa 2b cells did not induce bone formation in calvaria from mice lacking the Wnt co-receptor Lrp5. In human specimens, WNT7b was not expressed in normal prostate but was expressed in areas of high-grade prostate intraepithelial neoplasia, in three of nine primary prostate tumor specimens and in 16 of 38 samples of bone metastases from prostate cancer. DKK1 was not expressed in normal or cancerous tissue but was expressed in two of three specimens of osteolytic bone metastases (P=0.0119). We conclude that MDA PCa 2b induces new bone formation through Wnt canonical signaling, that LRP5 mediates this effect, and that DKK1 is involved in the balance between bone formation and resorption that determines lesion phenotype.

Aberrant promoter methylation profile of bladder cancer and its relationship to clinicopathological features.

We investigated the aberrant promoter methylation profile of bladder cancers and correlated the data with clinicopathological findings. The methylation status of 10 genes was determined in 98 surgically resected bladder cancers, and we calculated the median methylation index (MI), a reflection of the methylated fraction of the genes tested. Methylation frequencies of the genes tested in bladder cancers were 36% for CDH1, 35% for RASSF1A and APC, 29% for CDH13, 16% for FHIT, 15% for RAR beta, 11% for GSTP1, 7% for p16(INK4A), 4% for DAPK, and 2% for MGMT. Methylation of four of the individual genes (CDH1, RASSF1A, APC, and CDH13) and the MI were significantly correlated with several parameters of poor prognosis (tumor grade, growth pattern, muscle invasion, tumor stage, and ploidy pattern). Methylation of CDH1, FHIT, and a high MI were associated with shortened survival. CDH1 methylation positive status was independently associated with poor survival in multivariate analyses. Our results suggest that the methylation profile may be a potential new biomarker of risk prediction in bladder cancer.

Basaloid squamous cell carcinoma occurring in the urinary bladder.

Basaloid squamous cell carcinoma is a recently described, distinct variant of squamous cell carcinoma that arises predominantly in the upper aerodigestive tract. Herein we report a case of basaloid squamous cell carcinoma arising in the urinary bladder. The patient was a 60-year-old woman who experienced intractable urinary tract infections following multiple corrective surgical procedures for incontinence. Biopsies of cystoscopically evident flat lesions were performed, and the patient subsequently underwent a radical cystectomy. Histologically, the lesions consisted of nests of basaloid cells with brisk mitotic activity, areas of squamous differentiation along with areas of squamous metaplasia, and squamous cell carcinoma in situ. These features are similar to those of basaloid squamous cell carcinoma described elsewhere in the body. To our knowledge, this is the first reported case of basaloid squamous cell carcinoma in the urinary bladder.

Peripheral T-cell lymphoma presenting as ascites: a case report and review of the literature.

Here we report an unusual case of T-cell lymphoma presenting as ascites. A 49-yr-old woman was admitted to the hospital for abdominal discomfort associated with increasing abdominal girth over the course of 3 mo. She also complained of nausea, vomiting, and diarrhea. On physical examination, a tense and distended abdomen and edema of the lower extremities were noted. Neither hepatosplenomegaly nor lymphadenopathy was found. A CT scan of the abdomen and pelvis showed a large abdominal/pelvic mass surrounding the small bowel and omentum and small nodes in the para-aortic and mesenteric regions. The cytospin prepared from the peritoneal fluid was hypercellular and composed of a population of monotonous, noncohesive cells with a high nuclear/cytoplasmic ratio and a single prominent central nucleolus. The cells were positive for leukocyte common antigen and Leu-22 (CD43) but negative for keratin, L26, UCHL-1, kappa, lambda, CD3, Ki-1 (CD30), S-100, and carcinoembryonic antigen. Morphologic and immunologic findings were suggestive of T-cell immunoblastic lymphoma. Peripheral T-cell lymphomas rarely present as ascites; this case demonstrates the value of effusion cytology in making this diagnosis.