Stathmin as a surrogate marker of phosphatidylinositol-3-kinase pathway activity: Towards precision medicine in HPV-negative head & neck squamous cell carcinoma.

In order to assess Stathmin as an immunohistochemical (IHC) indicator of phosphatidylinositol 3-kinase (PI3K) pathway activity in HPV-negative head & neck squamous cell carcinoma (HNSCC), we compared Stathmin IHC to expression of other pathway components. We also evaluated the relationship between Stathmin IHC and the mutational status of four key pathway genes. Finally, we ascertained whether Stathmin IHC correlates with tumor grade or primary site. Correlation exists between high Stathmin expression and high pAKT1 expression, indicating a role for Stathmin IHC as a marker of pathway activity. Our analysis did not show correlation between Stathmin IHC and mutation of the four genes evaluated. We also observed an association between high Stathmin expression and oropharyngeal primary site. Our results suggest utility of Stathmin IHC as an indicator of PI3K pathway activity, and thereby demonstrate potential relevance of Stathmin IHC in the context of HNSCC.

Practical Considerations Relating to Routine Clinical Biomarker Testing for Non-small Cell Lung Cancer: Focus on Testing for RET Fusions.

For patients with advanced non-small cell lung cancer, genomic profiling of tumors to identify potentially targetable alterations and thereby inform treatment selection is now part of standard care. While molecular analyses are primarily focused on actionable biomarkers associated with regulatory agency-approved therapies, there are a number of emerging biomarkers linked to investigational agents in advanced stages of clinical development will become approved agents. A particularly timely example is the reported data and US Food and Drug Administration approval of highly specific small molecule inhibitors of the proto-oncogene tyrosine-protein kinase receptor RET indicate that testing for tumor RET gene fusions in patients with NSCLC has become clinically important. As the number of biomarkers to be tested in NSCLC grows, it becomes increasingly important to optimize and prioritize the use of biopsy tissue, in order to both continue to allow accurate histopathological diagnosis and also to support concurrent genomic profiling to identify perhaps relatively uncommon genetic events. In order to provide practical expert consensus guidance to optimize processes facilitating genomic testing in NSCLC and to overcome barriers to access and implementation, a multidisciplinary advisory board was held in New York, on January 30, 2019. The panel comprised physicians involved in sample procurement (interventional radiologists and a thoracic surgeon), surgical pathologists specializing in the lung, molecular pathologists, and thoracic oncologists. Particular consideration was given to the key barriers faced by these experts in establishing institutional genomic screening programs for NSCLC. Potential solutions have been devised in the form of consensus opinions that might be used to help resolve such issues.

Interobserver Variability in the Histopathologic Assessment of Extrathyroidal Extension of Well Differentiated Thyroid Carcinoma Supports the New American Joint Committee on Cancer Eighth Edition Criteria for Tumor Staging.

Background: Extrathyroidal extension (ETE) by papillary and follicular thyroid carcinoma can be associated with increased risk of tumor recurrence and mortality. In the seventh edition of its Cancer Staging Manual, the American Joint Committee on Cancer (AJCC) defined minimal ETE as the involvement of skeletal muscle (i.e., strap muscles) or perithyroidal soft tissue. The eighth edition of the AJCC Cancer Staging Manual has changed the criteria so that only grossly evident (macroscopic) ETE involving strap muscles (not microscopic ETE involving perithyroidal soft tissue) affects tumor staging. Summary: Concordance of identifying microscopic ETE (as well as extranodal extension by carcinoma metastatic to lymph nodes) was previously evaluated among 11 expert endocrine pathologists. The overall agreement rate was slight when rendering a diagnosis of ETE. Concordance was highest when pathologists assessed the spatial relationship of carcinoma to skeletal muscle. This article discusses the significance of these findings. It also reviews relevant anatomic and developmental considerations related to the boundaries of the thyroid. Conclusions: The results of the concordance study provide additional rationale supporting stringent criteria for diagnosing ETE, as proposed by the eighth edition of the AJCC Cancer Staging Manual. It is expected that these rigid morphologic criteria will potentially reduce interobserver variability and enhance consistency in the diagnosis and staging of thyroid carcinoma.

Salivary gland anlage tumor: molecular profiling sheds light on a morphologic question.

OBJECTIVE: Salivary gland anlage tumor (SGAT), previously described as a squamous proliferative lesion or "congenital pleomorphic adenoma," is a rare, benign entity that presents within the first months of life. It occurs almost exclusively in the nasopharynx or posterior nasal cavity and demonstrates a biphasic composition of epithelial and mesenchymal elements. Although the clinical and histologic features of SGAT are well described, its etiology remains poorly understood. SGAT is currently considered a hamartoma rather than a neoplasm, partly because of its benign behavior and lack of reported recurrence after treatment. However, investigators have not yet evaluated this concept by using genomic methods. STUDY DESIGN: Here, we present 3 SGAT cases where we performed whole-exome sequencing. RESULTS: Examination of sequence data, with specific attention to variants affecting 964 cancer-related genes, showed no plausible driver-type alterations. CONCLUSIONS: The lack of apparent driver mutations supports the classification of this entity as a hamartomatous (nonneoplastic) process.

Thyroid tumors with follicular architecture.

Thyroid tumors with follicular architecture encompass a considerable array of distinct entities. These lesions share significant morphologic overlap, but portend different prognostic and therapeutic implications. Due to their similar growth patterns, distinction between these tumors can be difficult; remarkable interobserver variability exists, even between expert endocrine pathologists. Given the diagnostic challenges associated with these lesions, establishment of the correct diagnosis requires adequate gross examination protocol, careful attention to morphologic features and pathologic context, as well as-increasingly-adjunct molecular findings. In this review, we summarize the salient features of various follicular thyroid tumors, with special emphasis on the recently defined category of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), as well as the molecular pathology of these lesions.

Pathologic Reporting of Tall-Cell Variant of Papillary Thyroid Cancer: Have We Reached a Consensus?

BACKGROUND: Tall-cell variant (TCV) is widely believed to be a more aggressive subtype of papillary thyroid carcinoma (PTC). Despite the significance of TCV with respect to risk stratification and therapeutic decision making, its diagnosis is subject to inter-observer variability. This study aimed to determine the level of agreement among expert pathologists in the identification and reporting of TCV. METHODS: Seventeen surgical resections for thyroid cancer containing the diagnostic term "tall cell" in their pathology reports and 22 cases diagnosed as classical PTC were selected. Cases were digitalized, and 14 expert pathologists reviewed the scanned slides blinded to the original interpretation. Each pathologist designated each case as TCV or not and answered multiple questions about diagnostic histopathologic features of TCV. RESULTS: The overall strength of agreement for identifying TCV was fair (Fleiss kappa 0.34), and the proportion of observed agreement was 0.70. Of 22 cases originally diagnosed as PTC classical variant, 15 (68%) were reclassified as TCV by at least one expert pathologist. It was noted that four different definitions for TCV were used by the participants based on various combinations of cell height to width (H:W) ratio and the percentage of tumor cells showing that specific ratio. All pathologists agreed that the diagnosis of TCV does not rely solely on a specific H:W ratio. CONCLUSIONS: Pathologic reporting of TCV varies among pathologists. This disagreement is a result of the lack of unanimous diagnostic criteria and variation in individual pathologists' interpretations. These discrepancies lead to over- and under-diagnosis of TCV, which has significant implications in patient management. It is imperative to understand this variability in diagnosis TCV as it relates to risk stratification and interpretation of clinical studies related to this histologic subtype of PTC. Further studies are needed to reach consensus on the diagnostic criteria of TCV.

Precision Medicine in Children and Young Adults with Hematologic Malignancies and Blood Disorders: The Columbia University Experience.

BACKGROUND: The advent of comprehensive genomic profiling has markedly advanced the understanding of the biology of pediatric hematological malignancies, however, its application to clinical care is still unclear. We present our experience integrating genomic data into the clinical management of children with high-risk hematologic malignancies and blood disorders and describe the broad impact that genomic profiling has in multiple aspects of patient care. METHODS: The Precision in Pediatric Sequencing Program at Columbia University Medical Center instituted prospective clinical next-generation sequencing (NGS) for high-risk malignancies and blood disorders. Testing included cancer whole exome sequencing (WES) of matched tumor-normal samples or targeted sequencing of 467 cancer-associated genes, when sample adequacy was a concern, and tumor transcriptome (RNA-seq). A multidisciplinary molecular tumor board conducted interpretation of results and final tiered reports were transmitted to the electronic medical record according to patient preferences. RESULTS: Sixty-nine samples from 56 patients with high-risk hematologic malignancies and blood disorders were sequenced. Patients carried diagnoses of myeloid malignancy (n = 25), lymphoid malignancy (n = 25), or histiocytic disorder (n = 6). Six patients had only constitutional WES, performed for a suspicion of an inherited predisposition for their disease. For the remaining 50 patients, tumor was sequenced with matched normal tissue when available. The mean number of somatic variants per sample was low across the different disease categories (2.85 variants/sample). Interestingly, a gene fusion was identified by RNA-seq in 58% of samples who had adequate RNA available for testing. Molecular profiling of tumor tissue led to clinically impactful findings in 90% of patients. Forty patients (80%) had at least one targetable gene variant or fusion identified in their tumor tissue; however, only seven received targeted therapy. Importantly, NGS findings contributed to the refinement of diagnosis and prognosis for 34% of patients. Known or likely pathogenic germline alterations were discovered in 24% of patients involving cancer predisposition genes in 12% of cases. CONCLUSION: Incorporating whole exome and transcriptome profiling of tumor and normal tissue into clinical practice is feasible, and the value that comprehensive testing provides extends beyond the ability to target-specific mutations.

Clinical Genomic Profiling of a Diverse Array of Oncology Specimens at a Large Academic Cancer Center: Identification of Targetable Variants and Experience with Reimbursement.

Large cancer panels are being increasingly used in the practice of precision medicine to generate genomic profiles of tumors with the goal of identifying targetable variants and guiding eligibility for clinical trials. To facilitate identification of mutations in a broad range of solid and hematological malignancies, a 467-gene oncology panel (Columbia Combined Cancer Panel) was developed in collaboration with pathologists and oncologists and is currently available and in use for clinical diagnostics. Herein, we share our experience with this testing in an academic medical center. Of 255 submitted specimens, which encompassed a diverse range of tumor types, we were able to successfully sequence 92%. The Columbia Combined Cancer Panel assay led to the detection of a targetable variant in 48.7% of cases. However, although we show good clinical performance and diagnostic yield, third-party reimbursement has been poor. Reimbursement from government and third-party payers using the 81455 Current Procedural Terminology code was at 19.4% of billed costs, and 55% of cases were rejected on first submission. Likely contributing factors to this low level of reimbursement are the delays in valuation of the 81455 Current Procedural Terminology code and in establishing national or local coverage determinations. In the absence of additional demonstrations of clinical utility and improved patient outcomes, we expect the reimbursement environment will continue to limit the availability of this testing more broadly.

Implementation of next generation sequencing into pediatric hematology-oncology practice: moving beyond actionable alterations.

BACKGROUND: Molecular characterization has the potential to advance the management of pediatric cancer and high-risk hematologic disease. The clinical integration of genome sequencing into standard clinical practice has been limited and the potential utility of genome sequencing to identify clinically impactful information beyond targetable alterations has been underestimated. METHODS: The Precision in Pediatric Sequencing (PIPseq) Program at Columbia University Medical Center instituted prospective clinical next generation sequencing (NGS) for pediatric cancer and hematologic disorders at risk for treatment failure. We performed cancer whole exome sequencing (WES) of patient-matched tumor-normal samples and RNA sequencing (RNA-seq) of tumor to identify sequence variants, fusion transcripts, relative gene expression, and copy number variation (CNV). A directed cancer gene panel assay was used when sample adequacy was a concern. Constitutional WES of patients and parents was performed when a constitutionally encoded disease was suspected. Results were initially reviewed by a molecular pathologist and subsequently by a multi-disciplinary molecular tumor board. Clinical reports were issued to the ordering physician and posted to the patient's electronic medical record. RESULTS: NGS was performed on tumor and/or normal tissue from 101 high-risk pediatric patients. Potentially actionable alterations were identified in 38% of patients, of which only 16% subsequently received matched therapy. In an additional 38% of patients, the genomic data provided clinically relevant information of diagnostic, prognostic, or pharmacogenomic significance. RNA-seq was clinically impactful in 37/65 patients (57%) providing diagnostic and/or prognostic information for 17 patients (26%) and identified therapeutic targets in 15 patients (23%). Known or likely pathogenic germline alterations were discovered in 18/90 patients (20%) with 14% having germline alternations in cancer predisposition genes. American College of Medical Genetics (ACMG) secondary findings were identified in six patients. CONCLUSIONS: Our results demonstrate the feasibility of incorporating clinical NGS into pediatric hematology-oncology practice. Beyond the identification of actionable alterations, the ability to avoid ineffective/inappropriate therapies, make a definitive diagnosis, and identify pharmacogenomic modifiers is clinically impactful. Taking a more inclusive view of potential clinical utility, 66% of cases tested through our program had clinically impactful findings and samples interrogated with both WES and RNA-seq resulted in data that impacted clinical decisions in 75% of cases.

A case study of an integrative genomic and experimental therapeutic approach for rare tumors: identification of vulnerabilities in a pediatric poorly differentiated carcinoma.

BACKGROUND: Precision medicine approaches are ideally suited for rare tumors where comprehensive characterization may have diagnostic, prognostic, and therapeutic value. We describe the clinical case and molecular characterization of an adolescent with metastatic poorly differentiated carcinoma (PDC). Given the rarity and poor prognosis associated with PDC in children, we utilized genomic analysis and preclinical models to validate oncogenic drivers and identify molecular vulnerabilities. METHODS: We utilized whole exome sequencing (WES) and transcriptome analysis to identify germline and somatic alterations in the patient's tumor. In silico and in vitro studies were used to determine the functional consequences of genomic alterations. Primary tumor was used to generate a patient-derived xenograft (PDX) model, which was used for in vivo assessment of predicted therapeutic options. RESULTS: WES revealed a novel germline frameshift variant (p.E1554fs) in APC, establishing a diagnosis of Gardner syndrome, along with a somatic nonsense (p.R790*) APC mutation in the tumor. Somatic mutations in TP53, MAX, BRAF, ROS1, and RPTOR were also identified and transcriptome and immunohistochemical analyses suggested hyperactivation of the Wnt/ß-catenin and AKT/mTOR pathways. In silico and biochemical assays demonstrated that the MAX p.R60Q and BRAF p.K483E mutations were activating mutations, whereas the ROS1 and RPTOR mutations were of lower utility for therapeutic targeting. Utilizing a patient-specific PDX model, we demonstrated in vivo activity of mTOR inhibition with temsirolimus and partial response to inhibition of MEK. CONCLUSIONS: This clinical case illustrates the depth of investigation necessary to fully characterize the functional significance of the breadth of alterations identified through genomic analysis.

Inter-Observer Variation in the Pathologic Identification of Extranodal Extension in Nodal Metastasis from Papillary Thyroid Carcinoma.

BACKGROUND: Extranodal extension (ENE) in lymph node metastases has been shown to worsen the prognosis of papillary thyroid cancer (PTC). Despite the clinical significance of ENE, there are no stringent criteria for its microscopic diagnosis, and its identification is subject to inter-observer variability. The objective of this study was to determine the level of agreement among expert pathologists in the identification of ENE in PTC cases. METHODS: Eleven expert pathologists from the United States, Italy, and Canada were asked to review 61 scanned slides of representative permanent sections of PTC specimens from Mount Sinai Beth Israel Medical Center in New York. Each slide was evaluated for the presence of ENE. The pathologists were also asked to report the criteria they use to identify ENE. RESULTS: The overall strength of agreement in identifying ENE was only fair (κ = 0.35), and the proportion of observed agreement was 0.68. The proportions of observed agreement for the identification of perinodal structures (fat, nerve, skeletal, and thick-walled vessel involvement) ranged from 0.61 to 0.997. CONCLUSIONS: Overall agreement for the identification of ENE is poor. The lack of agreement results from both variation in pathologists' identification of features and disagreement on the histologic criteria for ENE. This lack of concordance may help explain some of the discordant information regarding prognosis in clinical studies when this feature is identified.

Inter-Observer Variation in the Pathologic Identification of Minimal Extrathyroidal Extension in Papillary Thyroid Carcinoma.

BACKGROUND: Extrathyroidal extension (ETE) is a significant prognostic factor in papillary thyroid carcinoma (PTC). Minimal extrathyroidal extension (mETE) is characterized by involvement of the sternothyroid muscle or perithyroid soft tissue, and is generally identified by light microscope examination. Patients with mETE, identified pathologically, are automatically upstaged to pT3. However, the prognostic implications of mETE have been a source of controversy in the literature. Moreover, there is also controversy surrounding the identification of mETE on pathological specimens. The objective of this study was to determine the level of agreement among expert pathologists in the identification of mETE in PTC cases. METHODS: Eleven expert pathologists from the United States, Italy, and Canada were asked to perform a review of 69 scanned slides of representative permanent sections of PTC specimens. Each slide was evaluated for the presence of mETE. The pathologists were also asked to list the criteria they use to identify mETE. RESULTS: The overall strength of agreement for identifying mETE was slight (κ = 0.14). Inter-pathologist agreement was best for perithyroidal skeletal muscle involvement (κ = 0.46, moderate agreement) and worst for invasion around thick-walled vascular structures (κ = 0.02, slight agreement). In addition, there was disagreement over the constellation of histologic features that are diagnostic for mETE, which affected overall agreement for diagnosing mETE. CONCLUSIONS: Overall agreement for the identification of mETE is poor. Disagreement is a result of both variation in individual pathologists' interpretations of specimens and disagreement on the histologic criteria for mETE. Thus, the utility of mETE in staging and treatment of PTC is brought into question. The lack of concordance may explain the apparent lack of agreement regarding the prognostic significance of this pathologic feature.

Loss of Activin Receptor Type 1B Accelerates Development of Intraductal Papillary Mucinous Neoplasms in Mice With Activated KRAS.

BACKGROUND & AIMS: Activin, a member of the transforming growth factor-ß (TGFB) family, might be involved in pancreatic tumorigenesis, similar to other members of the TGFB family. Human pancreatic ductal adenocarcinomas contain somatic mutations in the activin A receptor type IB (ACVR1B) gene, indicating that ACVR1B could be a suppressor of pancreatic tumorigenesis. METHODS: We disrupted Acvr1b specifically in pancreata of mice (Acvr1b(flox/flox);Pdx1-Cre mice) and crossed them with LSL-KRAS(G12D) mice, which express an activated form of KRAS and develop spontaneous pancreatic tumors. The resulting Acvr1b(flox/flox);LSL-KRAS(G12D);Pdx1-Cre mice were monitored; pancreatic tissues were collected and analyzed by histology and immunohistochemical analyses. We also analyzed p16(flox/flox);LSL-Kras(G12D);Pdx1-Cre mice and Cre-negative littermates (controls). Genomic DNA, total RNA, and protein were isolated from mouse tissues and primary pancreatic tumor cell lines and analyzed by reverse-transcription polymerase chain reaction, sequencing, and immunoblot analyses. Human intraductal papillary mucinous neoplasm (IPMN) specimens were analyzed by immunohistochemistry. RESULTS: Loss of ACVR1B from pancreata of mice increased the proliferation of pancreatic epithelial cells, led to formation of acinar to ductal metaplasia, and induced focal inflammatory changes compared with control mice. Disruption of Acvr1b in LSL-KRAS(G12D);Pdx1-Cre mice accelerated the growth of pancreatic IPMNs compared with LSL-KRAS(G12D);Pdx1-Cre mice, but did not alter growth of pancreatic intraepithelial neoplasias. We associated perinuclear localization of the activated NOTCH4 intracellular domain to the apical cytoplasm of neoplastic cells with the expansion of IPMN lesions in Acvr1b(flox/flox);LSL-KRAS(G12D);Pdx1-Cre mice. Loss of the gene that encodes p16 (Cdkn2a) was required for progression of IPMNs to pancreatic ductal adenocarcinomas in Acvr1b(flox/flox);LSL-Kras(G12D);Pdx1-Cre mice. We also observed progressive loss of p16 in human IPMNs of increasing grades. CONCLUSIONS: Loss of ACVR1B accelerates growth of mutant KRAS-induced pancreatic IPMNs in mice; this process appears to involve NOTCH4 and loss of p16. ACVR1B suppresses early stages of pancreatic tumorigenesis; the activin signaling pathway therefore might be a therapeutic target for pancreatic cancer.

Close surgical margins after radical prostatectomy mimic biochemical recurrence rates of positive margins.

INTRODUCTION: The significance of a "close" but negative surgical margin after radical prostatectomy (RP) is controversial. We evaluated the effect of a close surgical margin (CSM) on biochemical recurrence (BCR) compared to a negative margin after RP. MATERIALS AND METHODS: Pathologic records of men who underwent RP from 2005-2011 were retrospectively reviewed. Margin status was classified as "positive" (PSM), "negative" (NSM), or "close" (<1mm from margin). BCR was defined as 2 consecutive postoperative prostate specific antigen measurements >0.2ng/ml. Probability of BCR was estimated using the Kaplan-Meier method and stratified by margin status. Univariable and multivariable Cox proportional hazards models were used to determine whether close margin status was associated with an increased rate of BCR. RESULTS: A total of 609 consecutive patients underwent RP (93% robotic) and had complete pathologic data. A total of 126 (20.7%) had PSM, 453 (74.4%) had NSM, and 30 (4.9%) had CSM (mean<0.44mm). The 3-year BCR-free survival for patients with CSM was similar to those with PSM (70.4% vs. 74.5%, log rank P = 0.66) and significantly worse than those with NSM (90%, log rank P<0.001). On multivariable regression, positive margin status (HR = 3.26, P<0.001) was significantly associated with a higher risk of BCR, along with close margins (HR = 2.7, P = 0.04). CONCLUSIONS: BCR for patients with CSM at RP is tantamount to PSM patients. CSM <1mm should be explicitly noted on pathology reports. Patients with this finding should be followed up closely and offered adjuvant therapy.

Oncogenic PIK3CA mutation and dysregulation in human salivary duct carcinoma.

Salivary duct carcinoma (SDC) is an aggressive malignant tumor with a high mortality, which resembles high-grade breast ductal carcinoma in morphology. The parotid gland is the most common location. Its molecular genetic characteristics remain largely unknown. We have previously reported high incidence of PIK3CA somatic mutations in head and neck squamous cell carcinoma, particularly in pharyngeal cancers. Here we examined the PIK3CA gene expression status and hotspot mutations in six cases of SDC by immunohistochemistry and genomic DNA sequencing. Immunohistochemistry showed that PIK3CA expression was elevated in all six patients with SDC. By DNA sequencing, two hotspot mutations of the PIK3CA gene, E545K (exon 9) and H1047R (exon 20), were identified in two of the six cases. Our results support that oncogenic PIK3CA is upregulated and frequently mutated in human SDC, adding evidence that PIK3CA oncogenic pathway is critical in the tumorigenesis of SDC, and may be a plausible drug target for this rare disease.

Pitfalls in the biopsy diagnosis of intraoral minor salivary gland neoplasms: diagnostic considerations and recommended approach.

Among the more common types of intraoral minor salivary gland neoplasms are pleomorphic adenoma, basal cell adenoma, polymorphous low-grade adenocarcinoma, and adenoid cystic carcinoma. These minor salivary gland neoplasms share similar morphologic features and to a large extent immunohistochemical findings. Differentiation between these benign and malignant neoplasms is often predicated on the presence or absence of invasion. As such, in the presence of limited tissue sampling that typifies the initial testing modalities, including fine needle aspiration biopsy and/or incisional biopsy, it often is not possible to differentiate a benign from malignant minor salivary gland neoplasm. The diagnostic difficulties arise from the absence in needle or incisional biopsy of the tumor's periphery to determine whether infiltrative growth is or is not present. In this manuscript we discuss limitations and considerations associated with evaluation of incisional biopsies of intraoral minor salivary gland tumors. We offer a diagnostic approach to evaluating these biopsies, and suggest diagnostic terminology for biopsy specimens in which distinction between benignancy and malignancy is not feasible. The pathologist's approach to this distinction is critical, as treatment of benign neoplasms is generally conservative, whereas malignant lesions may warrant more aggressive management.

Loss of PTEN expression is associated with poor prognosis in patients with intraductal papillary mucinous neoplasms of the pancreas.

PURPOSE: Previously, we reported PIK3CA gene mutations in high-grade intraductal papillary mucinous neoplasms (IPMN). However, the contribution of phosphatidylinositol-3 kinase pathway (PI3K) dysregulation to pancreatic carcinogenesis is not fully understood and its prognostic value unknown. We investigated the dysregulation of the PI3K signaling pathway in IPMN and its clinical implication. EXPERIMENTAL DESIGN: Thirty-six IPMN specimens were examined by novel mutant-enriched sequencing methods for hot-spot mutations in the PIK3CA and AKT1 genes. PIK3CA and AKT1 gene amplifications and loss of heterozygosity at the PTEN locus were also evaluated. In addition, the expression levels of PDPK1/PDK1, PTEN, and Ki67 were analyzed by immunohistochemistry. RESULTS: Three cases carrying the E17K mutation in the AKT1 gene and one case harboring the H1047R mutation in the PIK3CA gene were detected among the 36 cases. PDK1 was significantly overexpressed in the high-grade IPMN versus low-grade IPMN (P = 0.034) and in pancreatic and intestinal-type of IPMN versus gastric-type of IPMN (P = 0.020). Loss of PTEN expression was strongly associated with presence of invasive carcinoma and poor survival in these IPMN patients (P = 0.014). CONCLUSION: This is the first report of AKT1 mutations in IPMN. Our data indicate that oncogenic activation of the PI3K pathway can contribute to the progression of IPMN, in particular loss of PTEN expression. This finding suggests the potential employment of PI3K pathway-targeted therapies for IPMN patients. The incorporation of PTEN expression status in making surgical decisions may also benefit IPMN patients and should warrant further investigation.

Portal Hypertension, Nodular Regenerative Hyperplasia of the Liver, and Obstructive Portal Venopathy due to Metastatic Breast Cancer.

Nodular regenerative hyperplasia (NRH) of the liver is associated with noncirrhotic portal hypertension, rheumatologic and hematologic disorders, administration of certain drugs, and other underlying conditions. This report describes a 64-year-old man with clinically presumed cirrhosis who presented to our institution with coffee-ground emesis, esophageal varices, ascites, and encephalopathy. Eleven years earlier he had been treated for breast cancer with mastectomy and chemo-radiotherapy. He died suddenly, and the autopsy showed no evidence of cirrhosis but instead demonstrated NRH with extensive emboli of recurrent breast carcinoma within the portal vein and its intrahepatic branches. Neoplastic occlusion of the portal vein as a cause of presinusoidal noncirrhotic portal hypertension has not previously been reported for metastatic breast carcinoma. This case highlights the importance of obstructive portal venopathy in the pathogenesis of NRH as well as the diagnostic difficulties that may be encountered in determining the cause of portal hypertension.