Ductal and acinar components of mixed prostatic adenocarcinoma frequently have a common clonal origin.

BACKGROUND: Ductal adenocarcinoma (DA) is an aggressive subtype of prostate cancer. It is most commonly seen in mixed tumors together with conventional acinar adenocarcinoma (AA). The genetic profile of DA and its clonal origin is not fully characterized. OBJECTIVE: To investigate whether DA represents a distinct genetic subtype and to investigate the somatic relationship between the ductal and acinar components of mixed cancers. DESIGN, SETTING, AND PARTICIPANTS: In 17 radical prostatectomy specimens ductal and acinar tumor components from the same tumor foci were dissected. DNA was extracted and genomic sequencing performed. After exclusion of two cases with low cell yield, 15 paired samples remained for analysis. RESULTS: In 12 of 15 cases a common somatic denominator was identified, while three cases had clonally separate components. In DA, TMPRSS2-ERG gene fusions were detected in 47% (7/15), clonal FOXA1 alterations in 33% (5/15) and SPOP alterations in 27% (4/15) of cases. In one case KIAA1549-BRAF fusion was identified. Genome doubling events, resulting in an increased ploidy, were identified in the DA in 53% (8/15) of cases, but not seen in any AA. PTEN and CTNNB1 alterations were enriched in DA (6/15) but not seen in any AA. No cancers showed microsatellite instability or high tumor mutation burden. CONCLUSIONS: Ductal and acinar prostate adenocarcinoma components of mixed tumors most often share the same origin and are clonally related. DA components in mixed tumor often exhibit genome doubling events resulting in aneuploidy, consistent with the aggressive nature of high grade prostate cancer.

Different Responses to Neoadjuvant Chemotherapy in Urothelial Carcinoma Molecular Subtypes.

BACKGROUND: For muscle-invasive bladder cancer (MIBC), no tissue biomarkers are available for clinical use to predict response to neoadjuvant chemotherapy. OBJECTIVE: To investigate how molecular subtypes impact pathological response and survival in patients receiving preoperative cisplatin-based chemotherapy. DESIGN, SETTING, AND PARTICIPANTS: Classification of a retrospective cohort of 149 patients was performed by tumor transcriptomic profiling and immunostaining. A cohort treated with radical cystectomy alone and public data sets were used for comparison and external validation. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Complete pathological response in the cystectomy specimen (ypT0N0) and survival were compared in predefined molecular subtypes. Differential gene expression and chemotherapy response were explored beyond molecular subtypes. RESULTS AND LIMITATIONS: Patients with genomically unstable (GU) and urothelial-like (Uro) tumors had higher proportions of complete pathological response (16/31 [52%] and 17/54 [31%]), versus five out of 24 (21%) with the basal/squamous (Ba/Sq) subtype following neoadjuvant chemotherapy and radical cystectomy. Molecular subtype was independently associated with improved survival for patients with GU tumors (hazard ratio [HR] 0.29, 95% confidence interval [CI]: 0.11-0.79) and UroC tumors (HR 0.37, 95% CI: 0.14-0.94) compared with Ba/Sq tumors, adjusting for clinical stage. In addition, expression of the gene coding for osteopontin (SPP1) showed a subtype-dependent effect on chemotherapy response. CONCLUSIONS: Urothelial cancer of the luminal-like (GU and Uro) subtypes is more responsive to cisplatin-based neoadjuvant chemotherapy. A second-generation of subtype-specific biomarkers, for example, SPP1, may be a way forward to develop a more precision-based treatment approach for neoadjuvant chemotherapy in MIBC. PATIENT SUMMARY: This study shows that tumor classification by gene expression profiling and molecular subtyping can identify patients who are more likely to benefit from chemotherapy before radical cystectomy for muscle-invasive bladder cancer. Together with other markers for response, molecular subtypes could have a role in selective administration of such chemotherapy.

Mapping prostatic microscopic anisotropy using linear and spherical b-tensor encoding: A preliminary study.

PURPOSE: Tensor-valued diffusion encoding provides more specific information than conventional diffusion-weighted imaging (DWI), but has mainly been applied in neuroimaging studies. This study aimed to assess its potential for the imaging of prostate cancer (PCa). METHODS: Seventeen patients with histologically proven PCa were enrolled. DWI of the prostate was performed with linear and spherical tensor encoding using a maximal b-value of 1.5 ms/µm2 and a voxel size of 3 × 3 × 4 mm3 . The gamma-distribution model was used to estimate the mean diffusivity (MD), the isotropic kurtosis (MKI ), and the anisotropic kurtosis (MKA ). Regions of interest were placed in MR-defined cancerous tissues, as well as in apparently healthy tissues in the peripheral and transitional zones (PZs and TZs). RESULTS: DWI with linear and spherical encoding yielded different image contrasts at high b-values, which enabled the estimation of MKA and MKI . Compared with healthy tissue (PZs and TZs combined) the cancers displayed a significantly lower MD (P < .05), higher MKI (P < 10-5 ), and lower MKA (P < .05). Compared with the TZ, tissue in the PZ showed lower MD (P < 10-3 ) and higher MKA (P < 10-3 ). No significant differences were found between cancers of different Gleason scores, possibly because of the limited sample size. CONCLUSION: Tensor-valued diffusion encoding enabled mapping of MKA and MKI in the prostate. The elevated MKI in PCa compared with normal tissues suggests an elevated heterogeneity in the cancers. Increased in-plane resolution could improve tumor delineation in future studies.

Three-dimensional single-cell imaging for the analysis of RNA and protein expression in intact tumour biopsies.

Microscopy analysis of tumour samples is commonly performed on fixed, thinly sectioned and protein-labelled tissues. However, these examinations do not reveal the intricate three-dimensional structures of tumours, nor enable the detection of aberrant transcripts. Here, we report a method, which we name DIIFCO (for diagnosing in situ immunofluorescence-labelled cleared oncosamples), for the multimodal volumetric imaging of RNAs and proteins in intact tumour volumes and organoids. We used DIIFCO to spatially profile the expression of diverse coding RNAs and non-coding RNAs at the single-cell resolution in a variety of cancer tissues. Quantitative single-cell analysis revealed spatial niches of cancer stem-like cells, and showed that the niches were present at a higher density in triple-negative breast cancer tissue. The improved molecular phenotyping and histopathological diagnosis of cancers may lead to new insights into the biology of tumours of patients.

PD-L1 expression and deficient mismatch repair in ductal adenocarcinoma of the prostate.

This study aimed to investigate the expression of programmed death receptor ligand 1 (PD-L1) and deficient mismatch repair (dMMR) in ductal adenocarcinoma of the prostate. A tissue microarray of 32 ductal and 42 grade-matched acinar adenocarcinomas was used. Slides were stained for PD-L1, PD-L2, MMR proteins, CD4 and CD8. PD-L1 expression in tumor cells was only seen in 3% (1/34) of ductal and 5% (2/42) of acinar adenocarcinomas (p = 1.0), while PD-L1 expression in tumor-infiltrating immune cells was seen in 29% (10/34) of ductal and 14% (6/42) of acinar adenocarcinomas (p = 0.16). dMMR, as defined by loss of one or more of the MMR proteins, was identified in 5% (4/73) of cases, including 1 ductal and 3 acinar adenocarcinomas. There was a suggested association between infiltration of CD8+ lymphocytes and ductal subtype (p = 0.04) but not between CD4+ lymphocytes and tumor type (p = 0.28). The study shows that both dMMR and PD-L1 expression is uncommon in tumor cells of both ductal and acinar adenocarcinoma of the prostate, while PD-L1 expression in tumor-infiltrating immune cells is a more common finding.

TERT promoter mutational screening as a tool to predict malignant behaviour in follicular thyroid tumours-three examples from the clinical routine.

Follicular thyroid adenomas (FTAs) and carcinomas (FTCs), collectively the most common thyroid neoplasms, constitute a significant clinical challenge since histological evidence of invasive behaviour is required for a malignant diagnosis. Small subsets of FTAs relapse as manifest malignant FTCs, indicating that histology is not always adequate to predict malignant potential. Lately, recurrent mutations in the promoter of the Telomerase reverse transcriptase (TERT) gene have been coupled to FTCs, whereas FTAs usually lack this aberrancy. We describe three patients with follicular thyroid tumours in which TERT promoter mutational screening was employed as part of the clinical work-up to pinpoint malignant potential. In two retrospective analyses of seemingly benign lesions, the detected mutations predicted future skeletal metastases, and in one prospective case, the mutational screening led to a different clinical management of the afflicted patient. We therefore consider TERT promoter mutational screening an adjunct tool of value in equivocal cases.

Macroscopic features of prostate cancer.

This study investigates the macroscopic features of prostate cancers in unfixed prostatic tissue. For the study 514 radical prostatectomy specimens received at the Karolinska University Hospital were examined. The glands were bisected horizontally prior to fixation. Features on the cut surface of the prostate that were considered conclusive or suspicious for cancer were seen in 52% and 24% of specimens, respectively. In microscopic sections from these areas substantial cancers (≥2 mm) were found in 94% and 69%, of glands, respectively. When no cancer was seen grossly, substantial cancers were still identified histologically in 56% of cases on the cut surface of the prostate. Of substantial tumours 58% had distinct gross findings and 20% were considered to be suspicious for cancer on macroscopic examination. It was noted that gross assessment of the tumour diameter usually underestimated the microscopic extent of the tumour (p < 0.001). Of tumours that could be identified conclusively, 30% were tan, 30% white, 16% yellow and 24% orange. Transition zone tumours were most often orange (61%) while peripheral zone tumours were usually tan or white (35% and 33%). All macroscopically identifiable cancers were poorly circumscribed. Among substantial cancers, transition zone tumours were less frequently visualised than peripheral zone tumours (33% and 13%, respectively; p < 0.001). Findings conclusive for cancer macroscopically usually predict microscopic cancer, but substantial cancers may be present even if no cancer is seen grossly. Transition zone tumours are more difficult than peripheral zone tumours to visualise macroscopically.

Publisher Correction: Whole-tissue biopsy phenotyping of three-dimensional tumours reveals patterns of cancer heterogeneity.

In this Article originally published, owing to a technical error, author affiliations were incorrectly assigned in the HTML version; the PDF was correct. These errors have now been corrected.

A novel technique for biobanking of large sections of radical prostatectomy specimens.

AIMS: Harvesting of unfixed tissue from radical prostatectomy specimens for research purposes is challenging. Many prostate cancers cannot be identified at gross inspection, and this tumour is notoriously multifocal and heterogeneous. We aimed to develop a technique to allow detailed topographic analysis and the sampling of a sufficient amount of tumour without jeopardising clinical reporting. METHODS AND RESULTS: A custom-made double-bladed knife was utilised for cutting a 4-mm-thick horizontal section of the prostate. The slices were split into segments that were frozen in gel, cryosections were cut, and RNA integrity numbers (RINs) were analysed. Sections were cut from all blocks of 20 cases, and the cutting time was monitored. Slides were scanned, and the slices were digitally reconstructed. Cutting frozen sections of an entire slice took 79-253 min (mean 162 min). Tumour was detected in frozen sections of 85% (17/20) of cases and in 46% (72/155) of blocks. The morphological quality was determined to be excellent, and RIN values were high (mean 8.9). CONCLUSIONS: This novel protocol for biobanking of fresh tissue from prostatectomy specimens provides sufficient tumour material for research purposes, while also enabling reporting of histopathology. The harvesting of a full tissue slice facilitates studies of tumour multifocality and heterogeneity.

Whole-tissue biopsy phenotyping of three-dimensional tumours reveals patterns of cancer heterogeneity.

Intratumoral heterogeneity is a critical factor when diagnosing and treating patients with cancer. Marked differences in the genetic and epigenetic backgrounds of cancer cells have been revealed by advances in genome sequencing, yet little is known about the phenotypic landscape and the spatial distribution of intratumoral heterogeneity within solid tumours. Here, we show that three-dimensional light-sheet microscopy of cleared solid tumours can identify unique patterns of phenotypic heterogeneity, in the epithelial-to-mesenchymal transition and in angiogenesis, at single-cell resolution in whole formalin-fixed paraffin-embedded (FFPE) biopsy samples. We also show that cleared FFPE samples can be re-embedded in paraffin after examination for future use, and that our tumour-phenotyping pipeline can determine tumour stage and stratify patient prognosis from clinical samples with higher accuracy than current diagnostic methods, thus facilitating the design of more efficient cancer therapies.

mTOR inhibitors counteract tamoxifen-induced activation of breast cancer stem cells.

Breast cancer cells with stem cell characteristics (CSC) are a distinct cell population with phenotypic similarities to mammary stem cells. CSCs are important drivers of tumorigenesis and the metastatic process. Tamoxifen is the most widely used hormonal therapy for estrogen receptor (ER) positive cancers. In our study, tamoxifen was effective in reducing proliferation of ER + adherent cancer cells, but not their CSC population. We isolated, expanded and incubated CSC from seven breast cancers with or without tamoxifen. By genome-wide transcriptional analysis we identified tamoxifen-induced transcriptional pathways associated with ribosomal biogenesis and mRNA translation, both regulated by the mTOR-pathway. We observed induction of the key mTOR downstream targets S6K1, S6RP and 4E-BP1 in-patient derived CSCs by tamoxifen on protein level. Using the mTOR inhibitors rapamycin, everolimus and PF-04691502 (a dual PI3K/mTOR inhibitor) and in combination with tamoxifen, significant reduction in mammosphere formation was observed. Hence, we suggest that the CSC population play a significant role during endocrine resistance through activity of the mTOR pathway. In addition, tamoxifen further stimulates the mTOR-pathway but can be antagonized using mTOR-inhibitors.

Detection of smoothelin expression in the urinary bladder is strongly dependent on pretreatment conditions: a critical analysis with possible consequences for cancer staging.

Distinguishing urinary bladder muscularis propria (MP) from muscularis mucosae (MM) is crucial in bladder cancer staging. Immunohistochemical staining for the smooth muscle-specific protein smoothelin has been reported to be a robust marker for MP. The aim of this study was to investigate how smoothelin immunostaining in the bladder varies with pretreatment techniques and if it can be used to discriminate between MM and MP. Immunohistochemistry (IHC) for smoothelin was performed on nontumoral sections from 18 cystectomy specimens using three different pretreatment protocols. The immunoreactivity of MM, MP and blood vessels was scored semiquantitatively. Staining intensity depended strongly on the different pretreatment protocols used. Heat-induced epitope retrieval (HIER) in alkaline buffer resulted in the strongest staining with a moderate or strong immunostaining of the MP in 18/18 (100%) of cases, but in 11/18 (61%), the MM was moderately or strongly stained. HIER in acidic buffer resulted in a suboptimal staining of the MP. Enzymatic pretreatment resulted in absent or weak staining. In conclusion, smoothelin IHC is strongly dependent on epitope retrieval, and smoothelin staining did not discriminate reliably between MP and MM with any of the tested pretreatment protocols.

Protruding and non-protruding colon carcinomas originating in gut-associated lymphoid tissue.

BACKGROUND: Colon carcinomas arising in gut-associated lymphoid tissue (GALTC) are termed dome carcinomas (DC) because of their protruding phenotype. Only 8 GALTC cases have been reported in the literature. CASE REPORT: A female patient, aged 53, having a familial pedigree of colon cancer, uterine cervix cancer and brain tumour developed a signet-ring carcinoma in the cecum and 10 years later endometrial cancer. While asymptomatic, a plaque-like protrusion in the colon was detected at surveillance colonoscopy. Histology demonstrated a protruding GALTC. The surgical specimen showed four additional carcinomas: 2 GALTC (non-protruding) and 2 carcinomas in lymphoid-free colonic mucosa (LFCMC). CONCLUSION: Since adenomas could not be demonstrated neither previously nor in the colectomy specimen, it is suggested that the GALTCs in this patient may have followed the GALT-carcinoma pathway.