Utility of PTEN and ERG immunostaining for distinguishing high-grade PIN from intraductal carcinoma of the prostate on needle biopsy

Clinical Utility and Biologic Implications of Phosphatase and Tensin Homolog (PTEN) and ETS-related Gene (ERG) in Prostate Cancer

Phosphatase and tensin homolog (PTEN) and ETS-related gene (ERG) mutations are commonly found in prostate cancer. Although mouse studies have demonstrated that PTEN and ERG cooperatively interact during tumorigenesis, human studies examining these genes have been inconclusive. A systematic PubMed search including original articles assessing the pathogenesis of PTEN and ERG in prostate cancer was performed. Studies examining ERG's prognostic significance have conflicting results. Studies examining PTEN and ERG simultaneously found these genes are likely to occur together, but cooperative tumorigenesis functions have not been conclusively established. PTEN mutations are associated with a range of prognostic features. However, the practical clinical utility of this information remains to be determined.

Histopathology of Prostate Cancer

This review focuses on histopathological aspects of carcinoma of the prostate. A tissue diagnosis of adenocarcinoma is often essential for establishing a diagnosis of prostate cancer, and the foundation for a tissue diagnosis is currently light microscopic examination of hematoxylin and eosin (H&E)-stained tissue sections. Markers detected by immunohistochemistry on tissue sections can support a diagnosis of adenocarcinoma that is primary in the prostate gland or metastatic. Histological variants of carcinoma of the prostate are important for diagnostic recognition of cancer or as clinicopathologic entities that have prognostic and/or therapeutic significance. Histological grading of adenocarcinoma of the prostate, including use of the 2014 International Society of Urological Pathology (ISUP) modified Gleason grades and the new grade groups, is one of the most powerful prognostic indicators for clinically localized prostate cancer, and is one of the most critical factors in determination of management of these patients.

Population-based study of the incidence and survival for intraductal carcinoma of the prostate

PURPOSE

The degree to which intraductal carcinoma of the prostate (IDC-P) affects clinical course remains poorly understood owing to small sample sizes from single-center studies. We sought to determine prognostic factors and outcomes associated with IDC-P in radical prostatectomy (RP) specimens.

MATERIALS AND METHODS

This is a retrospective study of RP during 2004 to 2013 using Surveillance, Epidemiology, and End Results to compare IDC-P with non-IDC-P. The effect of IDC-P on overall and disease-specific survival was assessed using Cox regression with a median follow-up of 4.8 years (interquartile range [IQR]: 2.6-7.0y; P = 0.01). Median prostate-specific antigen at diagnosis in IDC-P vs. non-IDC-P was similar (P = 0.23) at 6.2 (IQR: 4.6-13.0) vs. 6.1ng/ml (IQR: 4.6-9.8).

RESULTS

We identified 159,777 RP from 2004 to 2013, and 242 (0.002%) had IDC-P pathologic features. IDC-P was associated with a greater likelihood of extraprostatic stage, pT3/T4, 45.9% vs. 21.6% (P<0.001), higher grade, GS≥ 7, 79.3% vs. 62.7% (P<0.001), lymph node metastases, 5.8% vs. 2.4% (P<0.001), and positive surgical margins, 25.6% vs. 19.5% (P = 0.02). IDC-P was associated with a 3-fold increase in prostate cancer-specific mortality relative to non-IDC-P (hazard ratio = 3.0, 95% CI: 1.5-5.7; P<0.01). Limitations include retrospective design and potential underreporting of IDC-P that leads to underestimation of the true effect size.

CONCLUSIONS

The significance of IDC-P features has been recently recognized by the World Health Organization and it is associated with high-grade, extraprostatic features, and worse prostate cancer-specific mortality. Understanding its prognostic significance better guides adjuvant therapies and clinical trials.

Precursor Lesions of Urologic Malignancies

CONTEXT

- Precursor lesions of urologic malignancies are established histopathologic entities, which are important not only to recognize for clinical purposes, but also to further investigate at the molecular level in order to gain a better understanding of the pathogenesis of these malignancies.

OBJECTIVE

- To provide a brief overview of precursor lesions to the most common malignancies that develop within the genitourinary tract with a focus on their clinical implications, histologic features, and molecular characteristics.

DATA SOURCES

- Literature review from PubMed, urologic pathology textbooks, and the 4th edition of the World Health Organization Classification of Tumours of the Urinary System and Male Genital Organs. All photomicrographs were taken from cases seen at Weill Cornell Medicine or from the authors' personal slide collections.

CONCLUSIONS

- The clinical importance and histologic criteria are well established for the known precursor lesions of the most common malignancies throughout the genitourinary tract, but further investigation is warranted at the molecular level to better understand the pathogenesis of these lesions. Such investigation may lead to better risk stratification of patients and potentially novel treatments.

Differential Diagnosis of Intraductal Lesions of the Prostate

The category of intraductal lesions of the prostate includes a range of primary prostatic and nonprostatic processes with wide variation in prognosis and recommended follow-up. Studies have shown that pathologists are uncomfortable with the diagnosis of these lesions and that the diagnostic reproducibility is low in this category. Despite the diagnostic difficulty, their accurate and reproducible diagnosis is critical for patient management. This review aims to highlight the diagnostic criteria, prognosis, and treatment implications of common intraductal lesions of the prostate. It focuses on the recognition of intraductal carcinoma of the prostate (IDC-P) in prostate needle biopsies and how to distinguish it from its common mimickers, including high-grade prostatic intraepithelial neoplasia, invasive cribriform prostatic adenocarcinoma, urothelial carcinoma extending into prostatic ducts, and prostatic ductal adenocarcinoma. IDC-P is independently associated with higher risk disease, and its identification in a needle biopsy, even in the absence of invasive carcinoma, should compel definitive treatment. Conversely, high-grade prostatic intraepithelial neoplasia has a much better prognosis and in limited quantities does not even warrant a repeat biopsy. IDC-P must be distinguished from urothelial carcinoma involving prostatic ducts, as recommended treatment varies markedly. Ductal adenocarcinoma may confuse the pathologist and clinician by overlapping terminology, and morphology may also mimic IDC-P on occasion. The use of ancillary testing with immunohistochemistry and molecular markers has also been reviewed.

Pathology and molecular updates in tumors of the prostate: towards a personalized approach

INTRODUCTION

Treatment planning in patients with prostate neoplasms and prostate cancer (PCa) is generally based on the clinical and pathological molecular markers obtained from prostate needle biopsy and/or radical prostatectomy specimens. Area covered: Pathology of prostate neoplasms is evolving rapidly. Emerging trends include new additions to the 2016 World Health Organization (WHO) tumor classification as well as expanded diagnostic utility of biomarkers and molecular testing in tissue specimens, liquid biopsies and urinary samples, with the following purposes: diagnosis, prognosis and prediction. Expert commentary: The new additions to the 2016 WHO tumor classification, which include pathological definition of Intraductal carcinoma of the prostate (IDC-P) and of a new grading system for PCa, as well as identification of molecular markers, such as TMPRSS2-ERG and AR-V7, may pave the way to personalized therapy for patients with prostate tumors.

Intraductal Carcinoma of the Prostate on Diagnostic Needle Biopsy Predicts Prostate Cancer Mortality: A Population-Based Study

BACKGROUND

Intraductal carcinoma of the prostate (IDC-P) is a distinct histopathologic feature associated with high-grade, advanced prostate cancer. Although studies have shown that IDC-P is a predictor of progression following surgical or radiation treatment for prostate cancer, there are sparse data regarding IDC-P on diagnostic needle biopsy as a prognosticator of prostate cancer mortality.

MATERIALS AND METHODS

This was a population-based study of all prostate cancer patients diagnosed using needle biopsy and without evidence of systemic disease between 1991 and 1999 within a defined geographic region of Norway. Patients were identified by cross-referencing the Norwegian Cancer Registry. Of 318 eligible patients, 283 had biopsy specimens available for central pathology review. Clinical data were obtained from medical charts. We examined whether IDC-P on diagnostic needle biopsy was associated with adverse clinicopathological features and prostate cancer mortality.

RESULTS

Patients with IDC-P on diagnostic needle biopsy had a more advanced stage and a higher Gleason score compared to patients without IDC-P. IDC-P was also associated with an intensively reactive stroma. The 10-year prostate cancer-specific survival was 69% for patients with IDC-P on diagnostic needle biopsy and 89% for patients without IDC-P (Log rank P-value < 0.005). The presence of IDC-P on diagnostic needle biopsy remained an independent predictor of prostate cancer mortality after adjustments for clinical prognostic factors and treatment. After adjustment for the newly implemented Grade Group system of prostate cancer, IDC-P showed a strong tendency toward statistical significance. However, IDC-P did not remain a statistically significant predictor in the multivariable analysis.

CONCLUSION

IDC-P on diagnostic needle biopsy is an indicator of prostate cancer with a high risk of mortality. Accordingly, a diagnosis of IDC-P on needle biopsy should be reported and considered a feature of high-risk prostate cancer. Moreover, the association between IDC-P and reactive stroma provides evidence in support of the idea that stromal factors facilitate carcinoma invasion to the prostatic acini and ducts. Prostate 77:859-865, 2017. © 2017 Wiley Periodicals, Inc.

Biomarker, Molecular, and Technologic Advances in Urologic Pathology, Oncology, and Imaging

Urologic pathology is evolving rapidly. Emerging trends include the expanded diagnostic utility of biomarkers and molecular testing, as well as adapting to the plethora of technical advances occurring in genitourinary oncology, surgical practice, and imaging. We illustrate those trends by highlighting our approach to the diagnostic workup of a few selected disease entities that pathologists may encounter, including newly recognized subtypes of renal cell carcinoma, pheochromocytoma, and prostate cancer, some of which harbor a distinctive chromosomal translocation, gene loss, or mutation. We illustrate applications of immunohistochemistry for differential diagnosis of needle core renal biopsies, intraductal carcinoma of the prostate, and amyloidosis and cite encouraging results from early studies using targeted gene expression panels to predict recurrence after prostate cancer surgery. At our institution, pathologists are working closely with urologic surgeons and interventional radiologists to explore the use of intraoperative frozen sections for margins and nerve sparing during robotic prostatectomy, to pioneer minimally invasive videoscopic inguinal lymphadenectomy, and to refine image-guided needle core biopsies and cryotherapy of prostate cancer as well as blue-light/fluorescence cystoscopy. This collaborative, multidisciplinary approach enhances clinical management and research, and optimizes the care of patients with urologic disorders.

New and Emerging Diagnostic and Prognostic Immunohistochemical Biomarkers in Prostate Pathology

The diagnosis of minimal prostatic adenocarcinoma can be challenging on prostate needle biopsy, and immunohistochemistry may be used to support the diagnosis of cancer. The International Society of Urologic Pathology currently recommends the use of the basal cell markers high-molecular-weight cytokeraratin and p63, and α-methylacyl-coenzyme-A racemase. However, there are caveats associated with the interpretation of these markers, particularly with benign mimickers. Another issue is that of early detection of presence and progression of disease and prediction of recurrence after clinical intervention. There remains a lack of reliable biomarkers to accurately predict low-risk cancer and avoid over treatment. As such, aggressive forms of prostate cancer may be missed and indolent disease may be subjected to unnecessary radical therapy. New biomarker discovery promises to improve early detection and prognosis and to provide targets for therapeutic interventions. In this review, we present the emerging immunohistochemical biomarkers of prostate cancer PTEN, ERG, FASN, MAGI-2, and SPINK1, and address their diagnostic and prognostic advantages and limitations.

Intraductal Carcinoma of the Prostate Gland: Recent Advances

Intraductal carcinoma of the prostate (IDC-P) is characterized by prostatic carcinoma involving ducts and/or acini. The presence of IDC-P is usually associated with a high-grade Gleason score, large tumor volume, and adverse prognostic parameters, including extraprostatic extension and seminal vesicle invasion. When present, IDC-P is associated with worse outcomes, regardless of treatment status. IDC-P is included in a broader diagnostic category of atypical cribriform lesions of the prostate gland. This category of lesions also includes high-grade prostatic intraepithelial neoplasia (HGPIN), urothelial carcinoma involving prostatic ducts or acini, and prostatic ductal adenocarcinoma, amongst other intraductal proliferations. Differentiating between these entities is important as they have differing therapeutic and prognostic implications for patients, although differential diagnosis thereof is not always straightforward. The present review discusses IDC-P in regards to its morphological characteristics, molecular features, and clinical outcomes. Given the current state of knowledge, the presence of IDC-P should be evaluated and documented correctly in both radical prostatectomy and needle biopsy specimens, and the clinical implications thereof should be taken into consideration during treatment and follow up.

Mutation Profiling Indicates High Grade Prostatic Intraepithelial Neoplasia as Distant Precursors of Adjacent Invasive Prostatic Adenocarcinoma

INTRODUCTION

High Grade Prostatic Intraepithelial Neoplasia (HGPIN) is the putative precursor lesion to prostatic adenocarcinoma (PCa), but the precise relationship between HGPIN and PCa remains unclear.

METHODS

We performed a molecular case study in which we studied mutation profiles of six tumor-associated HGPIN lesions in a single case of TMPRSS2:ERG fusion positive Gleason score 7 PCa that we had previously mapped for somatic mutations in adjacent Gleason patterns 3 and 4 foci, using microdissection and targeted deep-sequencing.

RESULTS

A total of 32 tumor-specific mutated sites were successfully amplified and sequenced, including 25 truncal mutations and 7 mutations that were specific to either the Gleason pattern 3 or pattern 4 foci. All six HGPIN foci shared the same tumor-specific TMPRSS2:ERG fusion breakpoint, establishing that they were all clonally related to the adjacent invasive tumor. Among the 32 gene targets mutated in the invasive tumor, only mutation of the OR2AP1 gene, a truncal mutation, was found in a single focus of HGPIN. The remaining gene targets that were successfully sequenced were wild-type in all other HGPIN foci.

DISCUSSION

This study demonstrates the feasibility of targeted mutation profiling of HGPIN lesions, which will be important to understand PCa tumorigenesis. The results in this case, showing a remarkable absence of truncal mutations in HGPIN lesions bearing the tumor-specific ERG fusion, indicate HGPIN lesions may be relatively stable genetically and argue against a stepwise clonal evolution model of HGPIN to PCa. Prostate 76:1227-1236, 2016. © 2016 Wiley Periodicals, Inc.

ERG and PTEN status of isolated high-grade PIN occurring in cystoprostatectomy specimens without invasive prostatic adenocarcinoma

High-grade prostatic intraepithelial neoplasia (HGPIN) is widely believed to represent a precursor to invasive prostatic adenocarcinoma. However, recent molecular studies have suggested that retrograde spread of invasive adenocarcinoma into pre-existing prostatic ducts can morphologically mimic HGPIN. Thus, previous molecular studies characterizing morphologically identified HGPIN occurring in radical prostatectomies or needle biopsies with concurrent invasive carcinoma may be partially confounded by intraductal spread of invasive tumor. To assess ERG and PTEN status in HGPIN foci likely to represent true precursor lesions in the prostate, we studied isolated HGPIN occurring without associated invasive adenocarcinoma in cystoprostatectomies performed at Johns Hopkins between 2009 and 2014. Of 344 cystoprostatectomies, 33% (115/344) contained invasive prostatic adenocarcinoma in the partially submitted prostate (10 blocks/case on average) and were excluded from the study. Of the remaining cases without sampled cancer, 32% (73/229) showed 133 separate foci of HGPIN and were immunostained for ERG and PTEN using genetically validated protocols. Of foci of HGPIN with evaluable staining, 7% (8/107) were positive for ERG. PTEN loss was not seen in any HGPIN lesion (0/88). Because these isolated HGPIN foci at cystoprostatectomy are unlikely to represent retrograde spread of invasive tumor, our study suggests that ERG rearrangement, but not PTEN loss, is present in a minority of potential neoplastic precursor lesions in the prostate.

Intraductal carcinoma of prostate (IDC-P): from obscure to significant

The concept of intraductal carcinoma of prostate (IDC-P) has evolved over the years and its clinicopathologic significance has come to be more clearly appreciated. In contrast to morphologically malignant intraductal lesions that represent earlier stages of the malignant process in other anatomic sites such as the breast, IDC-P has now been generally recognized as a prognostically unfavorable manifestation of later stage spreading of its invasive counterpart. We here briefly review the evolution of the IDC-P concept, the histological diagnostic criteria and differential diagnosis, the clinical significance, as well as recent molecular data of IDC-P.

The 2016 WHO Classification of Tumours of the Urinary System and Male Genital Organs-Part B: Prostate and Bladder Tumours

It has been 12 yr since the publication of the last World Health Organization (WHO) classification of tumours of the prostate and bladder. During this time, significant new knowledge has been generated about the pathology and genetics of these tumours. Intraductal carcinoma of the prostate is a newly recognized entity in the 2016 WHO classification. In most cases, it represents intraductal spread of aggressive prostatic carcinoma and should be separated from high-grade prostatic intraepithelial neoplasia. New acinar adenocarcinoma variants are microcystic adenocarcinoma and pleomorphic giant cell adenocarcinoma. Modifications to the Gleason grading system are incorporated into the 2016 WHO section on grading of prostate cancer, and it is recommended that the percentage of pattern 4 should be reported for Gleason score 7. The new WHO classification further recommends the recently developed prostate cancer grade grouping with five grade groups. For bladder cancer, the 2016 WHO classification continues to recommend the 1997 International Society of Urological Pathology grading classification. Newly described or better defined noninvasive urothelial lesions include urothelial dysplasia and urothelial proliferation of uncertain malignant potential, which is frequently identified in patients with a prior history of urothelial carcinoma. Invasive urothelial carcinoma with divergent differentiation refers to tumours with some percentage of "usual type" urothelial carcinoma combined with other morphologies. Pathologists should mention the percentage of divergent histologies in the pathology report.

PATIENT SUMMARY

Intraductal carcinoma of the prostate is a newly recognized entity in the 2016 World Health Organization classification. Better defined noninvasive urothelial lesions include urothelial dysplasia and urothelial proliferation of uncertain malignant potential.

Histopathological features of intra-ductal carcinoma of prostatic and high grade prostatic intraepithelialneoplasia and correlation with PTEN and P63

BACKGROUND

The main morphologic differential diagnosis of intra-ductal carcinoma of prostate (IDC-P) is high grade prostatic intraepithelialneoplasia (HGPIN). Since IDC-P, unlike PIN, was strongly correlated with aggressive prostate cancer, differentiation of these is too necessary. So we evaluated immunohistopathological patterns and the prognostic factors of IDC-P and HGPIN, in radical prostatectomy samples.

METHODS

We evaluated 250 radical prostatectomy and detected 210 cases of prostatic adenocarcinoma without IDC-P foci, 40 cases with adenocarcinoma concomitant IDC-P, and 40 cases HGPIN; therefore, we evaluated immunohistopathological criteria in these groups. Data were analyzed using SPSS and P-value <0.05 was considered as the statistical significant level.

RESULTS

PSA level was significantly higher in IDC-P compared with non-IDC-P patients (15.7 ± 3.1 vs. 10.2 ± 4.3, P = 0.041). All pathological and morphologic features, also invasions factors were higher in IDC-P compared to non-IDC-P groups (P < 0.001). P63 was positive expressed in all IDC-P and HGPIN specimen. PTEN protein was diffusely expressed in the cytoplasm of all HGPIN but in 4 (11.1%) of IDC-P. PTEN and P63 were negative in adenocarcinoma foci.

CONCLUSION

We found that IDC-P had a unique histoclinical feature and was strongly associated with poor prognostic factors. Diagnosis and report of IDC-P should be considered in all prostate specimens. Also, we recommend PTEN IHC application for differentiated IDC-P from HGPIN in biopsies.

The presence of intraductal carcinoma of the prostate in needle biopsy is a significant prognostic factor for prostate cancer patients with distant metastasis at initial presentation

Intraductal carcinoma of the prostate is an adverse prognostic factor in localized prostate cancer patients. However, whether it influences outcome of those patients with distant metastases discovered at initial diagnosis is unclear. Here, we evaluated whether the presence of intraductal carcinoma of the prostate in prostate needle biopsies is an adverse prognostic factor for cancer-specific survival and overall survival in such prostate cancer patients. We retrospectively enrolled 150 eligible patients. All patients received androgen-deprivation therapy and/or chemotherapy. Their age, performance status, pain, metastatic sites, clinical T stage, serum prostate-specific antigen, alkaline phosphatase, hemoglobin, Gleason score, and the presence of Gleason pattern 5 were analyzed. Primary end point was cancer-specific survival; secondary end points included prostate-specific antigen progression-free survival and overall survival. Fine and Gray's model and the Cox proportional hazards model were used as statistical tests. Intraductal carcinoma of the prostate was detected in 100 (67%) patients. At a median follow-up of 38 months, 79 patients (53%) had died of the disease and nine (6%) had died of other causes. The average time interval to cancer-related death was 28 months. On multivariate analysis, only intraductal carcinoma of the prostate was significantly associated with cancer-specific survival (P=0.018) and overall survival (P=0.001), and only the presence of Gleason pattern 5 was significantly associated with prostate-specific antigen progression-free survival (P=0.026). The presence of intraductal carcinoma of the prostate was the only significant prognostic parameter for cancer-specific survival and overall survival in prostate cancer patients with distant metastasis at presentation. These results may prove useful in planning future treatments.

Premalignancy in Prostate Cancer: Rethinking What we Know

High-grade prostatic intraepithelial neoplasia (PIN) has been accepted as the main precursor lesion to invasive adenocarcinoma of the prostate, and this is likely to be the case. However, in an unknown number of cases, lesions fulfilling the diagnostic criteria for high-grade PIN may actually represent intra-acinar or intraductal spread of invasive carcinoma. Intriguingly, this possibility would not contradict many of the findings of previous epidemiologic studies linking high-grade PIN to carcinoma or molecular pathologic studies showing similar genomic (e.g., TMPRSS2-ERG gene fusion) as well as epigenomic and molecular phenotypic alterations between high-grade PIN and carcinoma. Also, this possibility would be consistent with previous anatomic studies in prostate specimens linking high-grade PIN and carcinoma in autopsy and other whole prostate specimens. In addition, if some cases meeting morphologic criteria for PIN actually represent intra-acinar spread of invasive carcinoma, this could be an important potential confounder of the interpretation of past clinical trials enrolling patients presumed to be without carcinoma, who are at high risk of invasive carcinoma. Thus, in order to reduce possible bias in future study/trial designs, novel molecular pathology approaches are needed to decipher when an apparent PIN lesion may be intra-acinar/intra-ductal spread of an invasive cancer and when it truly represents a precursor state. Similar approaches are needed for lesions known as intraductal carcinoma to facilitate better classification of them as true intra-ductal/acinar spread on one hand or as precursor high-grade PIN (cribriform type) on the other hand; a number of such molecular approaches (e.g., coevaluating TMPRSS-ERG fusion and PTEN loss) are already showing excellent promise. Cancer Prev Res; 9(8); 648-56. ©2016 AACR.

Characterization of Heterogeneous Prostate Tumors in Targeted Pten Knockout Mice

Previously, we generated a preclinical mouse prostate tumor model based on PSA-Cre driven inactivation of Pten. In this model homogeneous hyperplastic prostates (4-5m) developed at older age (>10m) into tumors. Here, we describe the molecular and histological characterization of the tumors in order to better understand the processes that are associated with prostate tumorigenesis in this targeted mouse Pten knockout model. The morphologies of the tumors that developed were very heterogeneous. Different histopathological growth patterns could be identified, including intraductal carcinoma (IDC), adenocarcinoma and undifferentiated carcinoma, all strongly positive for the epithelial cell marker Cytokeratin (CK), and carcinosarcomas, which were negative for CK. IDC pattern was already detected in prostates of 7-8 month old mice, indicating that it could be a precursor stage. At more than 10 months IDC and carcinosarcoma were most frequently observed. Gene expression profiling discriminated essentially two molecular subtypes, denoted tumor class 1 (TC1) and tumor class 2 (TC2). TC1 tumors were characterized by high expression of epithelial markers like Cytokeratin 8 and E-Cadherin whereas TC2 tumors showed high expression of mesenchyme/stroma markers such as Snail and Fibronectin. These molecular subtypes corresponded with histological growth patterns: where TC1 tumors mainly represented adenocarcinoma/intraductal carcinoma, in TC2 tumors carcinosarcoma was the dominant growth pattern. Further molecular characterization of the prostate tumors revealed an increased expression of genes associated with the inflammatory response. Moreover, functional markers for senescence, proliferation, angiogenesis and apoptosis were higher expressed in tumors compared to hyperplasia. The highest expression of proliferation and angiogenesis markers was detected in TC2 tumors. Our data clearly showed that in the genetically well-defined PSA-Cre;Pten-loxP/loxP prostate tumor model, histopathological, molecular and biological heterogeneity occurred during later stages of tumor development.

[Intraductal carcinoma of the prostate]

For many tumor entities, especially in breast cancer, an intraductal carcinoma is generally perceived as a precursor lesion, which precedes the emergence of invasive carcinoma. Therefore, in addition to parameters of the invasive carcinoma, histological parameters of the intraductal component have always played an important role in therapy planning of breast cancer. This is different in prostate cancer and although the term "intraductal carcinoma" has long been propagated by some authors, its routine use remains rare and inconsistent. This is certainly not only due to the far simpler therapy options of prostate cancer, in which focal and organ-preserving therapies still play a subordinate role, but also due to substantial interobserver variation and our inconsistent perception of intraductal carcinomas. This article gives a brief overview of currently available literature on this topic and explains why intraductal carcinoma of the prostate deserves our attention. In contrast to breast cancer, intraductal carcinoma of the prostate usually represents a post-invasive lesion, in which an aggressive tumor exhibits spread into pre-existing ducts; however, in rare cases, intraductal carcinoma may represent a true precursor lesion.

Gleason Score 6 - Prostate Cancer or Benign Variant?

The leading motivation behind wanting to call a 'malignant' prostate lesion 'benign' is the evidence of indolent prostate cancer that is not associated with a fatal outcome and in part makes therapeutic measures such as surgery and radiotherapy appear like overtreatment for some or possibly the majority of such patients. The present article reviews the definitions of 'precancerous lesion' and 'cancer' from a histopathologic point of view as the basis and gold standard for diagnosis. It is clear that with the 2 modifications implemented since its first publication, the Gleason score as the grading system for prostate cancer has shifted towards a low malignant subgroup diagnosed as Gleason 6. The recommendation of the International Society of Urological Pathology to change the Gleason score to a 5-tiered system, starting with grade group 1, is presented here, and may help doctor-patient communication especially in the active surveillance setting.

Molecular evidence that invasive adenocarcinoma can mimic prostatic intraepithelial neoplasia (PIN) and intraductal carcinoma through retrograde glandular colonization

Prostate cancer often manifests as morphologically distinct tumour foci and is frequently found adjacent to presumed precursor lesions such as high-grade prostatic intraepithelial neoplasia (HGPIN). While there is some evidence to suggest that these lesions can be related and exist on a pathological and morphological continuum, the precise clonal and temporal relationships between precursor lesions and invasive cancers within individual tumours remain undefined. Here, we used molecular genetic, cytogenetic, and histological analyses to delineate clonal, temporal, and spatial relationships between HGPIN and cancer lesions with distinct morphological and molecular features. First, while confirming the previous finding that a substantial fraction of HGPIN lesions associated with ERG-positive cancers share rearrangements and overexpression of ERG, we found that a significant subset of such HGPIN glands exhibit only partial positivity for ERG. This suggests that such ERG-positive HGPIN cells either rapidly invade to form adenocarcinoma or represent cancer cells that have partially invaded the ductal and acinar space in a retrograde manner. To clarify these possibilities, we used ERG expression status and TMPRSS2-ERG genomic breakpoints as markers of clonality, and PTEN deletion status to track temporal evolution of clonally related lesions. We confirmed that morphologically distinct HGPIN and nearby invasive cancer lesions are clonally related. Further, we found that a significant fraction of ERG-positive, PTEN-negative HGPIN and intraductal carcinoma (IDC-P) lesions are most likely clonally derived from adjacent PTEN-negative adenocarcinomas, indicating that such PTEN-negative HGPIN and IDC-P lesions arise from, rather than give rise to, the nearby invasive adenocarcinoma. These data suggest that invasive adenocarcinoma can morphologically mimic HGPIN through retrograde colonization of benign glands with cancer cells. Similar clonal relationships were also seen for intraductal carcinoma adjacent to invasive adenocarcinoma. These findings represent a potentially undervalued indicator of pre-existing invasive prostate cancer and have significant implications for prostate cancer diagnosis and risk stratification.

Intraductal Carcinoma of the Prostate: Morphologic Features, Differential Diagnoses, Significance, and Reporting Practices

The differential diagnosis for atypical cribriform lesions of the prostate has become increasingly complex and includes intraductal carcinoma of the prostate, high-grade prostatic intraepithelial neoplasia, and atypical intraductal proliferations. In this review, we summarize the morphologic and molecular features and significance of intraductal carcinoma of the prostate. We also summarize our institution's strategy for reporting and treatment recommendations for intraductal carcinoma of the prostate.

The presence and clinical implication of intraductal carcinoma of prostate in metastatic castration resistant prostate cancer

BACKGROUND

Intraductal carcinoma of prostate (IDC-P) is always underestimated pathological pattern in prostate cancer and its role is still unclear in castration resistant prostate cancer (CRPC). This study was conducted to investigate the presence and the roles of IDC-P in patients with metastatic CRPC.

METHODS

45 patients with initially diagnosed metastatic prostate cancer and then progressed to CRPC, were included. All of them were received twice transperineal biopsies at the time of initial diagnosis and the time of CRPC. All samples were retrieved to detect the presence of IDC-P. PSA doubling time (PSADT) was considered as a parameter presenting the progression of CRPC. The relationships between IDC-P and other clinicopathological variables were analyzed.

RESULTS

IDC-P was found only in 20% (9/45) cases at initial diagnosis, whereas, it increased to 62.5% (28/45) at the time of CRPC (χ(2) = 16.568, P = 0.000). Compared to acinar adenocarcinoma components in tumor tissues, IDC-P components, especially solid subtype, had obviously poor/no response to androgen deprivation therapy (ADT). In addition, among patients treated with docetaxel-based chemotherapy (n = 24), patients with IDC-P also showed more unfavorable response than those without IDC-P (20% vs. 66.7%, P = 0.022). The presence of IDC-P and serum testosterone at the time of CRPC, were significantly associated with rapid disease progression. 13/28 (46.4%) CRPC with IDC-P had PSADT less than 30 days, while, only 1/17 (5.9%) patient without IDC-P had a less than 30 days PSADT (χ(2) = 8.114, P = 0.004). Limitations included the relative short follow-up time and a relative small cohort.

CONCLUSIONS

The presence of IDC-P was significantly associated with rapid progression of CRPC. And its presence could suggest the poor response to initial ADT and sequential docetaxel-based chemotherapy. Detection of IDC-P should be of importance in CRPC, and re-biopsy at the time of CRPC might be one of practical solutions. The mechanism of the ADT and docetaxel resistance to IDC-P needed to be further investigated.