Immunohistochemical comparison of MUC1, CA125, and Her2Neu in invasive micropapillary carcinoma of the urinary tract and typical invasive urothelial carcinoma with retraction artifact

Mass Spectrometric Analysis of Urinary N-Glycosylation Changes in Patients with Parkinson's Disease

Urine is thought to provide earlier and more sensitive molecular changes for biomarker discovery than blood. Numerous glycoproteins, peptides, and free glycans are present in urine through glomerular filtration of plasma, cell shedding, apoptosis, proteolytic cleavage, and exosome secretion. Urine biomarkers have enormous diagnostic potential, and the use of these biomarkers is a long-standing practice. The discovery of non-urological disease biomarkers from urine is also gaining attention due to its non-invasive sample collection and ease of analysis. Abnormal protein glycosylation in plasma or cerebrospinal fluid has been associated with Parkinson's disease, however, whether urine with Parkinson's disease has characteristic glycosylation remains to be explored. Here, we use mass spectrometry-based glycomics and glycoproteomics approaches to analyze urine samples for glycans, glycosites, and intact glycopeptides of urine samples. Reduced abundance of N-glycans was detected at the level of total glycans as well as specific glycosites of glycopeptides. The most abundant N-glycan in urine is S(6)1H5N4F1; S(6)2H5N4 and N4H4F1 are highly present in serum and urine, and 10 biantennary galactosylated N-glycans in the urine of PD patients were significantly decreased. The downregulation of sialylation may be due to the reduction of ST3GAL2. Site-specific N-glycosylation analysis revealed that AMBP, UMOD, and RNase1 have PD-specific N-glycosylation sites. GO and KEGG analysis revealed that N-glycosylation changes may provide clues to identify disease-specific glycosylation biomarkers in Parkinson's disease.

Invasive Micropapillary Urothelial Carcinoma: an Uncommon and Underreported Variant in Cystectomy Specimens

Conventional urothelial carcinoma is the most common histological type of urinary bladder carcinoma. The latest edition of the WHO classification of tumours of the urothelial tract lays special emphasis on the ability of urothelial tumours to exhibit divergent differentiation with multiple histologic variants and a diverse genomic landscape. The presence of a micropapillary component (MPC) in urothelial carcinoma is associated with high-grade disease and poor response to intravesical chemotherapy. The present study aims to enumerate the clinicohistological features of urothelial carcinomas with micropapillary differentiation. Slides from 144 radical cystectomy specimens received over 6 years were reviewed independently by two pathologists. A predominant histological pattern along with co-existing pathology was noted. Of these, five cases were pure micropapillary carcinomas, four had conventional urothelial carcinoma with a MPC, one had a microscopic tumour at the mucosal surface, and two cases showed micropapillary histology in the lymph node metastasis, following transurethral resection of bladder tumour and Bacillus Calmette-Guerin therapy. The tumours with pure micropapillary carcinoma presented with a higher pathological stage and poor overall survival. Organ and lymph node metastasis was noted in five and eight cases, respectively, of which six showed a micropapillary pattern in the lymph nodes. Micropapillary urothelial carcinoma is a rare and aggressive variant of urothelial carcinoma with unique histologic features. This variant is often missed and underreported in biopsy and surgical resection specimens. Since the presence of MPC confers a poorer prognosis, the identification and reporting of this entity are important.

Trousseau's Syndrome Presenting as Multiple Cerebral Infarctions Caused by Mucin-producing Bladder Micropapillary Urothelial Cancer

We herein report a 70-year-old man with recurrent multiple cerebral infarctions under warfarin therapy who was finally diagnosed with Trousseau's syndrome resulting from advanced bladder cancer. A histological examination of the mesenteric lymph nodes revealed metastasis of micropapillary urothelial cancer with positive mucin markers CA125 and MUC1. Blood examinations also indicated elevated tumor markers, such as CA19-9 and CA125. To our knowledge, this is the first report of Trousseau's syndrome in a patient with bladder micropapillary urothelial cancer in which mucin involvement was clearly proven by histological and serological examinations.

Cancer Antigen 15-3 Serum Level as a Biomarker for Advanced Micropapillary Urothelial Carcinoma of the Bladder: A Case Report

A 73-year-old woman with no history of disease was referred to our hospital with fatigue and joint pain. Screening blood test showed that her cancer antigen 15-3 (CA 15-3) serum level was elevated to 36.6 U/mL, and a contrast-enhanced computed tomography scan revealed a bladder tumor without metastasis. Cystoscopy showed a papillary and a small kissing tumor, and the histopathological analysis of the bladder tumor obtained by transurethral resection (TUR) showed invasive urothelial carcinoma (UC) with micropapillary variant (pT1). At 4 weeks after TUR, the CA 15-3 serum level was markedly increased to 180.6 U/mL, and radiographic examinations revealed multiple regional and nonregional lymph node metastases. The patient received systemic therapy with gemcitabine and cisplatin. After 3 cycles of chemotherapy, the size of all lymph node metastases reduced by 80% in diameter, and the CA 15-3 serum level decreased from 238.2 to 11.4 U/mL. Immunohistological analysis showed that the bladder tumor was positive for mucin 1, of which CA 15-3 is an epitope. In our patient, changes in the CA 15-3 serum levels were in congruence with the clinical course of advanced micropapillary UC (MPUC). Therefore, the CA 15-3 serum level may be a potentially valuable biomarker for MPUC.

The optimal management of variant histology in muscle invasive bladder cancer

Bladder cancer is a heterogenous disease that is associated with tangible mortality in muscle invasive disease. The WHO 2016 classification of urothelial tumours reflects the contemporary approach towards histological variants in bladder cancer, including variants of urothelial carcinoma (UC) and non-urothelial variants. This review focuses on variant histology in UC, and discusses the importance of accurate histological diagnosis, and subsequent risk stratification and therapeutic decision making based on proper variant recognition. Most urothelial variants are associated with poorer outcomes compared to conventional UC, although some perform reasonably better. However, high quality evidence detailing optimal treatment and survival outcomes are still lacking in literature, due to the rarity of these cases.

Development and validation of a nomogram for urothelial cancer in patients with chronic kidney disease

Urothelial cancer (UC) is a common kidney cancer in Taiwan and patients with chronic kidney disease (CKD) are more at risk for UC than the general population. The diagnostic value of urine analysis and urine cytology is limited, especially in CKD patients. The aim of the study is to develop a nomogram to predict the risk of UC in CKD patients. We enrolled 169 UC patients and 1383 CKD patients from 9 hospitals in Taiwan between 2012 and 2015. CA125, HE4, clinical characteristics, and medical history were analyzed using multivariable logistic regression for its association with UC. A nomogram was developed to predict the risk of UC and was validated using Bootstrap. CA125 was associated with UC in CKD patients (OR: 5.91, 95% CI: 3.24–10.77) but HE4 was not (OR: 1.29, 95% CI: 0.67–2.35). A nomogram based on patients’ age, estimated glomerular filtration rate, CA125 (log transformed), smoking, exposure of environmental toxin, use of nonsteroid anti-inflammatory drugs, and use of traditional Chinese medicine was conducted. The AUC of the nomogram was 0.90 (95% CI: 0.86–0.92, p < 0.01). Serum CA125 may identify UC patients from CKD patients but has limited diagnostic value due to low sensitivity. The diagnostic value of serum CA125 level can be improved by the combination with clinical characteristics including age, renal function, and medical history.

Prognostic and therapeutic role of HER2 expression in micropapillary carcinoma of the bladder

Micropapillary carcinoma of the bladder (MPBC) is a variant type of infiltrating urothelial carcinoma, which portends a poor biological behavior in terms of disease stage at first diagnosis and clinical outcome; its peculiar morphology raises issues concerning the ability of tumor detection by imaging techniques and proper biopsy procedure, and the appropriate treatment for non-muscle infiltrating and muscle-infiltrating MPBC remains a matter of debate. On the basis of its established prognostic and therapeutic role in breast and gastro-esophageal cancer in the first instance, the human epidermal growth factor receptor-2 (HER2) has been investigated in selected case series of MPBC over the last 10 years. The aim of the present review was to summarize the existing evidence on HER2 status in MPBC, and to discuss its present and future utility in risk assessment and treatment choice of this uncommon, yet aggressive, disease.

Cell Polarity Reversal Distinguishes True Micropapillary Growth From Retraction Artifact in Invasive Urothelial Carcinoma

Focal micropapillary features in invasive urothelial carcinoma is sometimes difficult to distinguish from retraction artifact morphologically. Cell polarity reversal has been demonstrated in micropapillary tumors by epithelial membrane antigen (EMA) immunostaining. We have previously described the use of E-cadherin as a cell polarity marker in ovarian micropapillary serous borderline tumors. The aim of this study was to evaluate the utility of immunohistochemistry for EMA and E-cadherin in differentiating micropapillary urothelial carcinoma from retraction artifact. We identified 29 invasive urothelial carcinomas with micropapillary features and 30 invasive urothelial carcinomas without reported micropapillary features but with areas of retraction artifact. Cell polarity reversal was considered present if E-cadherin showed membranous apical cup-like staining or if EMA demonstrated a well-defined basal staining towards the stroma. Twenty-seven of 29 cases (93%) of urothelial carcinoma with micropapillary features demonstrated EMA or E-cadherin staining patterns consistent with cell polarity reversal. Staining consistent with micropapillary architecture was identified with both markers in 20 of these 27 cases (74%). Six cases showed reversal of polarity by E-cadherin alone, whereas 1 case showed polarity reversal by EMA alone. Retraction artifacts showed circumferential staining by E-cadherin and lacked well-defined basal staining by EMA. Three cases originally classified as with retraction artifact showed reversal of cell polarity by both EMA and E-cadherin and were reclassified as micropapillary. Our data show that pathologists can reliably make this distinction in most cases. However, in some cases with ambiguous features, EMA and E-cadherin immunostaining may aid in resolving this diagnostic dilemma.

Urinary Bladder Pathology: World Health Organization Classification and American Joint Committee on Cancer Staging Update

Context.—

Since the publication of the previous World Health Organization (WHO) Classification of Tumours on the Pathology and Genetics of Tumours of the Urinary System and Male Genital Organs in 2004, significant new knowledge has been generated regarding the pathology and genetics of bladder neoplasia. Publication of the 2016 WHO “Blue Book” has codified that new data into updated recommendations for classification and prognostication. Similarly, the recent release of the 8th edition of the American Joint Committee on Cancer (AJCC) Cancer Staging Manual, which was implemented in January 2018, has also addressed staging criteria for bladder cancer in several unique settings to clarify their application.

Objective.—

To highlight subtle changes within the recent WHO and AJCC publications that may affect daily surgical pathology practice.

Data Sources.—

Peer-reviewed published literature, the 2016 WHO Classification of Tumours of the Urinary System and Male Genital Organs, and the 8th edition of the AJCC Cancer Staging Manual were reviewed.

Conclusions.—

Selected changes and/or clarifications are discussed and include classification of flat and papillary urothelial neoplasia, select variant patterns of invasive urothelial carcinoma, staging of invasive carcinoma in bladder diverticula, and staging of carcinomas involving the prostate gland.

High Grade T1 Papillary Urothelial Bladder Cancer Shows Prominent Peritumoral Retraction Clefting

Differentiation of noninvasive from invasive papillary urothelial carcinoma can be challenging due to inability of proper orientation and thermal damage of transurethrally obtained material. The aim of this study was to analyze the presence and extent of peritumoral retractions in pT1 compared to pTa papillary urothelial carcinoma. Since peritumoral retractions may result from altered expression profiles of extracellular matrix proteins, we additionally analyzed the expression of matrix metalloproteinase 2 (MMP-2) and interleukin 8 (IL-8) in these tumors. The study comprised 50 noninvasive (pTa) and 50 invasive (pT1) cases of transurethrally obtained primary papillary urothelial carcinomas. The invasive nature of nests showing peritumoral retractions was confirmed immunohistochemically using antibody against collagen IV. Staining for MMP-2 and IL-8 was evaluated semiquantitatively using immunohistochemical staining index, calculated by multiplying the percentage of positive cells and staining intensity. Peritumoral retractions were found in 32% of pT1 carcinomas but in none of the pTa carcinomas. All tumors showing peritumoral retraction were high grade tumors. There was no statistically significant correlation between the expression of MMP-2 or IL-8 and the presence of peritumoral retractions or stage of the tumor (pTa vs. pT1). A statistically significant but weak correlation was found between MMP-2 and IL-8 expression (χ2-test, p=0,015). There was no statistically significant correlation between the presence of peritumoral retractions or MMP-2 expression and tumor recurrence and progression. Our study shows that, in doubtful cases, when differentiating between pTa and pT1 stages of papillary urothelial carcinoma, the presence of peritumoral retractions could favor the diagnosis of invasive neoplasm.

Micropapillary morphology is an indicator of poor prognosis in patients with urothelial carcinoma treated with transurethral resection and radiochemotherapy

Purpose of this study was to evaluate prognostic impact of rare variants of urothelial bladder cancer (BC) after treatment with combined radiochemotherapy (RCT). To this end tumour tissue of 238 patients with urothelial carcinoma (UC) treated with transurethral resection of the bladder (TUR-B) and RCT with curative intent was collected. Histomorphological analysis included re-evaluation and semi-quantitative assessment of rare UC subtypes. Additionally, human epidermal growth factor receptor 2 (HER2) chromogenic in situ hybridisation (CISH) was performed in tumours with a micropapillary component exceeding 30 %. Long-term follow-up was available for 200 patients (range 3-282 months). Variant UC histology was found in 45 of 238 tumours, most frequently micropapillary UC (N = 17) including cases with a small fraction of tumour with micropapillary morphology. The mere presence of micropapillary morphology did not affect prognosis. In tumours with extensive (≥30 %) micropapillary morphology (N = 8) Kaplan-Meier analysis revealed significantly worse cancer specific survival (CSS) (P = 0.002) compared to conventional UC (mean survival times 97 months and 229 months, respectively). Univariate Cox regression analysis of cases with ≥30 % micropapillary morphology revealed a hazard ratio of 4.726 (95 % CI 1.629-13.714) for CSS (P = 0.004). CISH revealed HER2 gene amplification in 3/10 tumours with ≥30 % micropapillary component. In conclusion, for BC treated with TUR-B and RCT, the presence of micropapillary morphology in more than 30 % of the tumour is an adverse prognostic factor. Further studies are needed to evaluate a potential benefit of different, especially multimodal treatment strategies for micropapillary UC and also other subtypes of UC. Her2 represents a promising therapeutic target in a subset of micropapillary UC.

Consensus and conflict in invasive micropapillary carcinoma: a case report and review of the literature

Invasive micropapillary carcinoma (IMPC) is an aggressive histologic subtype of adenocarcinoma that has been gaining increased attention over the past twenty years. It is important to recognize IMPC due to its strong association with early lymphovascular invasion (LVI), high risk of lymph node metastasis, perineural invasion and poor prognosis. Controversies regarding IMPC include differentiating from retraction artifact and mimics, clinical significance of proportion of micropapillary component (MC), pathogenesis, biologic nature of the entity and consequently terminology, etc. We herein present a case of rectal IMPC arising from a tubulovillous adenoma. Since HER2 over-expression has been reported in IMPC of the breast and the bladder but never in the colorectum, given the availability of HER2 targeted therapy, HER2 protein expression in our case is examined by immunohistochemical study which shows weak incomplete membrane staining in less than 5% of cells. Literature is reviewed with emphasis on colorectal IMPC as well as aforementioned controversial topics. In summary, more study is needed to resolve the conflicts and build consensus on IMPC.

Immunohistochemical and molecular profiling of histologically defined apocrine carcinomas of the breast

Despite the marked improvement in the understanding of molecular mechanisms and classification of apocrine carcinoma, little is known about its specific molecular genetic alterations and potentially targetable biomarkers. In this study, we explored immunohistochemical and molecular genetic characteristics of 37 invasive apocrine carcinomas using immunohistochemistry (IHC), fluorescent in situ hybridization (FISH), multiplex ligation-dependent probe amplification (MLPA), and next-generation sequencing (NGS) assays. IHC revealed frequent E-cadherin expression (89%), moderate (16%) proliferation activity [Ki-67, phosphohistone H3], infrequent (~10%) expression of basal cell markers [CK5/6, CK14, p63, caveolin-1], loss of PTEN (83%), and overexpression of HER2 (32%), EGFR (41%), cyclin D1 (50%), and MUC-1 (88%). MLPA assay revealed gene copy gains of MYC, CCND1, ZNF703, CDH1, and TRAF4 in 50% or greater of the apocrine carcinomas, whereas gene copy losses frequently affected BRCA2 (75%), ADAM9 (54%), and BRCA1 (46%). HER2 gain, detected by MLPA in 38% of the cases, was in excellent concordance with HER2 results obtained by IHC/FISH (κ = 0.915, P < .001). TOP2A gain was observed in one case, while five cases (21%) exhibited TOP2A loss. Unsupervised hierarchical cluster analysis revealed two distinct clusters: HER2-positive and HER2-negative (P = .03 and .04, respectively). NGS assay revealed mutations of the TP53 (2 of 7, 29%), BRAF/KRAS (2 of 7, 29%), and PI3KCA/PTEN genes (7 of 7, 100%). We conclude that morphologically defined apocrine carcinomas exhibit complex molecular genetic alterations that are consistent with the "luminal-complex" phenotype. Some of the identified molecular targets are promising biomarkers; however, functional studies are needed to prove these observations.

Micropapillary bladder cancer: current treatment patterns and review of the literature

OBJECTIVES

No guidelines exist for the management of micropapillary bladder cancer (MPBC) and most reports of this variant of urothelial carcinoma are case series comprising small numbers of patients. We sought to determine current practice patterns for MPBC using a survey sent to the Society of Urologic Oncology (SUO) and to present those results in the setting of a comprehensive review of the existing literature.

MATERIALS AND METHODS

A survey developed by the Translational Science Working Group of the Bladder Cancer Advocacy Network-sponsored Think Tank meeting was distributed to members of the SUO. The results from 118 respondents were analyzed and presented with a literature review.

RESULTS

Most survey respondents were urologists, with 80% considering bladder cancer their primary area of interest. Although 78% of the respondents reported a dedicated genitourinary pathologist at their institution, there were discrepant opinions on how a pathologic diagnosis of MPBC is determined as well as variability on the proportion of MPBC that is clinically significant. Among them, 78% treat MPBC differently than conventional urothelial carcinoma, with 81% reporting that they would treat cT1 MPBC with upfront radical cystectomy. However, the respondents had split opinions regarding the sensitivity of MPBC to cisplatin-based chemotherapy, which affected utilization of neoadjuvant chemotherapy in muscle-invasive disease.

CONCLUSIONS

The management of MPBC is diverse among members of the SUO. Although most favors early cystectomy for cT1 MPBC, there is no consensus on the use of neoadjuvant chemotherapy for muscle-invasive MPBC.

Cytological findings of the micropapillary variant of urothelial carcinoma: a comparison with typical high-grade urothelial carcinoma

Background

Micropapillary variant of urothelial carcinoma (MPUC) showed distinct pathologic features and aggressive behavior. The cytologic findings of MPUC are still indistinct. In this study, we evaluated the cytological findings of MPUC compared with those of high-grade urothelial carcinoma (HGUC).

Methods

The voided urine cytology of 8 cases of MPUC and 8 cases of HGUC was reviewed. Following cytological parameters were evaluated: cellularity, background, number of small, tight papillary clusters, small acinar structure, scattered single cells, cytoplasmic features, nuclear-to-cytoplasmic ratio, nuclear pleomorphism, nuclear membrane irregularity, hyperchromasia, chromatin pattern and nucleoli.

Results

Compared to that of HGUC, cytology of MPUC showed large numbers of small, tight papillary clusters, small acinar structure, few numbers of single cells, and hyperchromatic nuclei. Other parameters were similar between the two groups; both groups showed similar cellularity, dense or vacuolated cytoplasm, moderate to severe nuclear pleomorphism, irregular nuclear membrane, coarse granular chromatin, and small and prominent nucleoli.

Conclusions

The urine cytology of MPUCs showed smaller and tighter papillary cell clusters, more small acinar structures, fewer numbers of scattered single cells, and more hyperchromatic nuclei than that of HGUC. These features can help to distinguish MPUC and HGUC and offer an early cytological diagnosis of MPUC.

Micropapillary carcinoma: new variant of prostatic acinar adenocarcinoma

A micropapillary variant of prostatic acinar adenocarcinoma has not been reported in the literature. Herein, we report a case of a 50-year-old patient who presented with an elevated prostate-specific antigen concentration and was subsequently diagnosed with prostatic acinar adenocarcinoma on biopsy. Radical prostatectomy specimen revealed prostatic carcinoma with Gleason score 4 + 5  =  9/10, with micropapillary component constituting 80% of tumor volume. Immunohistochemical studies of the prostate carcinoma showed a homogeneously positive prostate-specific antigen and α-methylacyl-CoA racemase, high-molecular-weight cytokeratin, and p63 protein cocktail pattern of staining in both micropapillary and conventional components. Pelvic lymph nodes were negative for metastatic disease. In contrast to the aggressive behavior of micropapillary carcinomas of other organs, the disease in our patient has thus far followed a more benign course, with low stage on presentation and a 2-year follow-up free of disease. However, prognostic correlation should be established on large series in order to assign this variant to a grade category within the Gleason scheme.

Host response in tumor diagnosis and prognosis: importance of immunologists and pathologists alliance

Pathologists and immunologists have collaborated over many years in their efforts to understand and properly diagnose cancer. The ability of pathologists to correctly diagnose this disease was facilitated by the development of immunohistology that utilized specificity of antibodies to distinguish between normal cells and cancer cells. Further boost was provided through the advent of monoclonal antibodies. The two disciplines are now together on the brink of a paradigm shift resulting from a better understanding of the importance for cancer diagnosis and prognosis to consider not only the characteristics of the cancer cells, but also the cancer microenvironment reflecting the host response to the disease. This new immunology and pathology alliance named "Immunoscore" will advance research in both disciplines as well as benefit patients.

Noninvasive micropapillary urothelial carcinoma: a clinicopathologic study of 18 cases

Noninvasive micropapillary urothelial carcinoma consists of slender tufts of urothelial carcinoma lacking fibrovascular cores analogous to ovarian papillary serous tumors of borderline malignancy. Eighteen noninvasive micropapillary urothelial carcinoma cases were identified from the Pathology Department of The Johns Hopkins Hospital (2000-2011). Patients lacked history of invasive urothelial carcinoma. Two patterns of noninvasive micropapillary urothelial carcinoma were identified: (1) as a variant of noninvasive high-grade papillary urothelial carcinoma (high-grade papillary urothelial carcinoma/micropapillary urothelial carcinoma) (n = 13 cases) and (2) as a variant of urothelial carcinoma in situ (carcinoma in situ/micropapillary urothelial carcinoma) (n = 5 cases with 2 of these patients also having high-grade papillary urothelial carcinoma/micropapillary urothelial carcinoma). Of 18 patients, 16 (88%) were male with a mean age of 71.8 years (range, 54-87 years). Of the 12 patients initially treated with surveillance, Bacillus-Calmette Guérin, or intravesical chemotherapy, 4 did not recur and were without evidence of disease at 6, 21, 24, and 39 months. Four patients experienced recurrences with 3 of them without evidence of disease at 36, 52, and 72 months and with the fourth whose last follow-up was at 84 months when recurrence occurred. One patient is alive at 11 months with disease, and 1 died of other causes at 1 month. Two patients progressed to pT2 and pT3 disease at 5 and 21 months, respectively. It is critical to differentiate and clearly specify in pathology reports whether micropapillary urothelial carcinoma is invasive or noninvasive because invasive micropapillary urothelial carcinoma is an aggressive disease with a high degree of understaging, whereas some cases of noninvasive micropapillary urothelial carcinoma are not necessarily associated with an adverse outcome.

Lymphovascular Invasion in Micropapillary Urothelial Carcinoma: A Study of 22 Cases

Context.—Micropapillary urothelial carcinoma (MPUC) is a known aggressive variant of urothelial carcinoma. However, the reasons for its aggressiveness remain unclear.

Objective.—To investigate the frequency of lymphovascular invasion in 22 cases of MPUC.

Design.—Consecutive tissue sections were stained with D2-40 and CD34 to highlight lymphovascular channels associated with MPUC. Spaces containing tumor cells were scored as positive for lymphovascular invasion if the staining pattern on immunohistochemistry was distinct and circumferential.

Results.—Of 22 cases, 21 (95%) had lymphovascular invasion on immunohistochemical staining, with 91% lymphatic invasion and 4% vascular invasion. Interestingly, 8 cases were originally signed out as negative for lymphovascular invasion on the basis of hematoxylin-eosin–stained sections; of these, 7 (88%) had focal lymphovascular invasion evident on immunohistochemical staining.

Conclusions.—Our results confirm that micropapillary lacunae are not lymphovascular channels. However, nearly all MPUC tumors (95% in this series) have evidence of lymphovascular invasion by immunohistochemical analysis. Our data support the use of micropapillary features as a morphologic marker for lymphovascular invasion and MPUC as an adverse histologic type of urothelial carcinoma.

Micropapillary variant of urothelial carcinoma

Micropapillary carcinoma (MPC) of urinary tract is an uncommon variant of urothelial carcinoma with significant diagnostic and prognostic implications. Though MPC shows characteristic microscopic features, there exists interobserver variability and also it needs to be differentiated from the metastasis from other organs. The prognosis is generally poor, depending on the proportion of the micropapillary component in some reports. Early cystectomy in cases with only lamina propria invasion may be indicated according to recent studies. This review outlines the general features of this entity and briefly comments on the controversies and the recent development.

The role of tumor hypoxia in MUC1-positive breast carcinomas

Mucin 1 (MUC1) is a glycoprotein that is expressed on apical cell membranes in a variety of normal tissues. MUC1 is involved in cell signaling, inhibition of cell-cell and cell matrix adhesion, apoptosis, proliferation, and transcription. Hypoxia is an important factor that promotes cancer metastasis and stimulates angiogenesis and tumor progression. Hypoxia inducible factor 1 (HIF-1α) and carbonic anhydrase IX (CAIX) are two molecules that are involved in this process. The role of hypoxia in MUC1+ invasive ductal breast carcinomas is not well established. In this study, the expression of MUC1 was correlated with the hypoxia-associated markers HIF-1α and CAIX, as well as several immunohistochemical markers and clinicopathologic features of prognostic significance in 243 invasive ductal carcinomas. MUC1 was overexpressed in 37.0% of patients and correlated with the expression of estrogen receptor (p = 0.0001), progesterone receptor (p = 0.0001), HIF-1α (p = 0.006), VEGF (p = 0.024), and p53 (p = 0.025). In breast cancer, MUC1 expression has been associated with increased degradation of inhibitor of NF-κB (IκBα), driving NF-κB to the nucleus and blocking apoptosis and promoting cell survival. We analyzed NF-κB expression in MUC1+ breast carcinoma and found a very significant relationship between these proteins (p = 0.0001). Our findings indicate that MUC1 may play a role in the regulation of hormone receptors by increasing the inactivation of p53 and targeting NF-κB to the nucleus. Our data also support the notion that activation of HIF-1α in MUC1+ breast carcinomas may modulate VEGF expression, allowing a metabolic adaptation to hypoxia.

HER2 gene amplification occurs frequently in the micropapillary variant of urothelial carcinoma: analysis by dual-color in situ hybridization

Human epidermal growth factor receptor-2 (HER2) is a well-recognized growth-promoting factor in cancer, although its application to urothelial carcinoma has been limited because of a low frequency of gene amplification. We evaluated HER2 protein expression and gene amplification in micropapillary carcinoma, a rare but highly aggressive variant of urothelial carcinoma by dual-color in situ hybridization. Gene amplification was defined by a HER2:CHR17 ratio of ≥2.2; low and high levels of amplification were further defined as <2.5 and ≥2.5, respectively. Immunohistochemistry was used to determine HER2 protein expression using the American Society of Clinical Oncology/College of American Pathologists Guidelines of HER2 staining. Protein expression, gene amplification, and chromosome 17 aneusomy were compared by Jonchkeere-Terpstra and Cochran-Armitage trend tests. In all, 19 of the 20 micropapillary carcinoma samples yielded usable dual-color in situ hybridization and immunohistochemistry results for evaluation. Overall, 68% (n=13) demonstrated HER2 protein expression of 2+ to 3+ staining. Gene amplification was present in 42% of samples (n=8), with 100% correlation with 2+ and 3+ protein expression. Gene amplification and protein expression were significantly associated (P=0.01). Overall, 53% of samples (n=10) had aneusomy of chromosome 17. Chromosome 17 aneusomy was present in approximately half of the samples evaluated, suggesting inherent genomic instability in this variant of urothelial carcinoma. However, increased HER2:CHR17 ratios demonstrate increased HER2 expression due to amplification in the majority of micropapillary carcinomas. These results suggest that HER2-targeted therapy may be successful on the genomic level in patients with this disease.

Emerging concepts in micropapillary urothelial carcinoma

Micropapillary urothelial carcinoma is a relatively uncommon variant of urothelial carcinoma, but its recognition carries important prognostic and treatment implications. Micropapillary morphology occurs in neoplasms arising in many different organ systems and displays aggressive biologic behavior regardless of its site of origin. On account of this association, micropapillary features in urothelial carcinoma should be reported regardless of whether the pattern is focal or dominant. The overall prognosis for micropapillary urothelial carcinoma is poor and recent studies suggest that early treatment with cystectomy could improve outcome, as these tumors are unlikely to respond to chemotherapy when used as a secondary treatment modality. This review discusses the histologic features required for diagnosis and the clinical significance of rendering a diagnosis of micropapillary urothelial carcinoma.