Assessing trends in breast care surveillance metrics after implementing surgeon-specific tracking and performance reporting in a large, integrated cancer network.

BACKGROUND: There are few quality metrics and benchmarks specific to surgical oncology. Development of a surgeon-level performance metrics system based on peer comparisons is hypothesized to positively influence surgical decision-making. This study established a tracking and reporting system comprised of evidence and consensus-based metrics to assess breast care delivered by individual surgeons. METHODS: Surgeons' performance is assessed by a surveillance tracking system of metrics pertaining to referrals and surgical elements. This retrospective analysis of prospectively collected breast care data reports on recurring 6-month and cumulative data from nine care locations from 2015 to 2021. RESULTS: Breast care was provided to 6659 patients by 41 surgeons. A total of 27 breast care metrics were evaluated over 7 years. Metrics with consistent, proficient results were retired after 18 months, including the rate of core biopsy, specimen orientation, and referrals to medical oncology, genetics, and fertility, among others. In clinically node-negative, hormone receptor-positive patients 70 years of age or older, the cumulative rate of sentinel lymph node (SLN) biopsy significantly decreased by 40% over 5.5 years (p < .001). The overall breast conservation rate for T0-T2 cancer increased 10% over 7 years. At the surgeon level, improvements were made in the median number of SLNs removed and in operative note documentation. CONCLUSIONS: Implementation of a surgeon-specific, peer comparison-based metric and tracking system has yielded substantive changes in breast care management. This process and governance structure can serve as a model for quantification of breast care at other institutions and for other disease sites.

Juvenile granulosa cell tumors: immunoreactivity for CD99 and Fli-1 and EWSR1 translocation status: a study of 11 cases.

The accurate diagnosis of a juvenile granulosa cell tumor (JGCT) can be challenging, as these neoplasms often exhibit morphologic features that overlap other ovarian neoplasms. In addition, the immunohistochemical profile exhibited by JGCT is fairly nonspecific and typically includes reactivity for CD99. Recently, we noted that JGCTs can show immunohistochemical expression of Fli-1, a transcription factor expressed by Ewing sarcoma, a neoplasm that is occasionally in the differential diagnosis of JGCT. We evaluated a series of JGCTs to determine whether Fli-1 is commonly expressed by these tumors and whether they demonstrate chromosomal arrangements in EWSR1. Cases diagnosed as JGCT (n=11) were immunohistochemically evaluated for expression of Fli-1 and CD99. Fluorescence in situ hybridization was performed on all cases to search for chromosomal rearrangements in EWSR1. All 11 of our cases exhibited positive immunohistochemical staining for Fli-1 and CD99. None of the cases demonstrated rearrangement in EWSR1 by fluorescence in situ hybridization. In cases of JGCT that cannot be reliably distinguished from Ewing sarcoma based on morphology and immunohistochemistry alone, fluorescence in situ hybridization testing for EWSR1 rearrangements seems to be a useful diagnostic adjunct for their separation.

Factors Associated with Early Discharge after Non-Emergent Right Colectomy for Colon Cancer: A NSQIP Analysis.

The National Surgical Quality Improvement Project (NSQIP) dataset was used to identify perioperative variables associated with the length of stay (LOS) and early discharge among cancer patients undergoing colectomy. Patients who underwent non-emergent right colectomy for colon cancer from 2012 to 2019 were identified from the NSQIP and colectomy-targeted databases. Postoperative LOS was analyzed based on postoperative day (POD) of discharge, with patients grouped into Early Discharge (POD 0-2), Standard Discharge (POD 3-5), or Late Discharge (POD ≥ 6) cohorts. Multivariable ordinal logistic regression was performed to identify risk factors associated with early discharge. The NSQIP query yielded 26,072 patients: 3684 (14%) in the Early Discharge, 13,414 (52%) in the Standard Discharge, and 8974 (34%) in the Late Discharge cohorts. The median LOS was 4.0 days (IQR: 3.0-7.0). Thirty-day readmission rates were 7% for Early Discharge, 8% for Standard Discharge, and 12% for Late Discharge. On multivariable regression analysis, risk factors significantly associated with a shorter LOS included independent functional status, minimally invasive approach, and absence of ostomy or additional bowel resection (all p < 0.001). Perioperative variables can be used to develop a model to identify patients eligible for early discharge after right colectomy for colon cancer. Efforts to decrease the overall median length of stay should focus on optimization of modifiable risk factors.

Radiation therapy for cT1-2 carcinoma of the palatine tonsil diagnosed via a simple tonsillectomy: Dosimetry and patterns of care in the IMRT era.

OBJECTIVE: Small carcinomas of the palatine tonsil are often diagnosed via simple tonsillectomy, a maneuver with non-therapeutic intent. Herein, practice patterns for this unique situation are evaluated. PATIENTS AND METHODS: A retrospective review was performed across 10 facilities to identify patients with cT1-2 squamous carcinomas of the tonsil diagnosed by simple tonsillectomy between 2010 and 2018. Patients who received curative-intent intensity modulated radiotherapy (IMRT) without additional surgery were included. Target volumes were reviewed, and cumulative incidences of local failure and severe late dysphagia were calculated. RESULTS: From 638 oropharyngeal patients, 91 were diagnosed via simple tonsillectomy. Definitive IMRT with no additional surgery to the primary site was utilized in 57, and three with gross residual disease were excluded, leaving 54 for analysis. Margins were negative in 13%, close (<5 mm) in 13%, microscopically positive in 61%, and not reported in 13%. Doses typically delivered to gross disease (68-70.2 Gy in 33-35 fx or 66 Gy/30 fx) were prescribed to the tonsil bed in 37 (69%). Sixteen patients (29%) received doses from 60 to 66 Gy (≤2 Gy/fx) and one received 50 Gy (2 Gy/fx). No local failures were observed. One late oropharyngeal soft tissue ulcer occurred, treated conservatively (grade 2). At five years, the cumulative incidence of severe late dysphagia was 17.4% (95% CI 6.1-28.8%). CONCLUSION: Small tonsil carcinomas diagnosed by simple tonsillectomy represent a niche subset with favorable oncologic outcomes. Regardless, radiation oncologists tend to deliver full-dose to the tonsil bed. The necessity of this routine could be questioned in the modern era.

Persistent opioid and benzodiazepine use after radical cystectomy in enhanced recovery after surgery (ERAS) patients.

OBJECTIVES: Opioid use, misuse, and diversion is of paramount concern in the United States. Radical cystectomy is typically managed with some component of opioid pain control. We evaluated persistent opioid and benzodiazepine use after radical cystectomy and assessed the impact of their preoperative use on this outcome. We also explored associations between preoperative use and perioperative outcomes. METHODS AND MATERIALS: We used prospectively maintained data from our enhanced recovery after surgery (ERAS) cystectomy database and the Prescription Reporting with Immediate Medication Utilization Mapping (PRIMUM) database to identify controlled substance prescriptions for radical cystectomy patients. We separated patients by frequency of preoperative opioid and/or benzodiazepine prescriptions (0, 1, 2+) and used these cohorts to explore persistent use (prescription 3-12 months after surgery) alongside perioperative outcomes. RESULTS: Our cohort included 257 patients undergoing cystectomy at a single institution from 2017 to 2021. Preoperative opioid and benzodiazepine prescriptions were documented for 120 (46.7%) and 26 (10.1%) patients, respectively. Persistent opioid use was observed in 20 (14.6%) of opioid-naive patients (no prescriptions in 9 months prior to surgery) while 13 (19.7%) patients with 1 preoperative prescription and 28 (51.9%) patients with 2 or more preoperative prescriptions demonstrated persistent use. New persistent benzodiazepine use occurred in 6 (2.6%) patients. Overall persistent benzodiazepine use was present in 11 (4.3%) patients. In a multivariable model, preoperative opioid and benzodiazepine prescriptions were associated with persistent opioid use (P < 0.001; P = 0.027 respectively). No association was identified between preoperative opioid or benzodiazepine usage and perioperative outcomes including length of stay, return of bowel function, inpatient opioid usage, inpatient or discharge complications, readmissions, or emergency department visits. Inpatient pain scores were noted to be higher in patients with ≥ 2 preoperative opioid prescriptions (P = 0.037). CONCLUSIONS: Persistent opioid use was present in 23.7% of patients, with a new persistent use rate of 14.6%. Benzodiazepine use was less frequent than opioids, with a small number demonstrating new persistent use. Preoperative opioid and benzodiazepine use is associated with persistent opioid use postoperatively. Preoperative opioid and benzodiazepine use did not affect perioperative outcomes in our cohort.

COVID-19 vaccine uptake trends in SARS-CoV-2 previously infected cancer patients.

Purpose: Cancer patients are at high risk of developing severe illness from SARS-CoV-2 infection, but risk is lowered with receipt of COVID-19 vaccine. COVID-19 vaccination uptake among previously infected cancer patients may be influenced by an assumption of natural immunity, predicted weak immune response, or concerns about vaccine safety. The objective of this study was to evaluate COVID-19 vaccine uptake trends in cancer patients previously infected with SARS-CoV-2. Materials and Methods: Medical records of 579 sequential cancer patients undergoing active treatment at Levine Cancer Institute who tested positive for COVID-19 between January 2020 and January 2021 were evaluated. Patients who died prior to vaccine eligibility were excluded from the analysis. Demographic, clinical, and COVID-19 related characteristics were analyzed to identify prognostic factors for COVID-19 vaccine uptake as this information could be important for health policy design for future pandemics. Results: Eighty-one patients died prior to the availability of COVID-19 vaccines. The acceptance rate of COVID-19 vaccination among 498 previously infected cancer patients was 54.6%. Of the patients with known vaccination dates, 76.8% received their first vaccine by April 17th, 2021. As of November 30, 2021, 23.7.% of eligible patients were boosted. In univariate models, older age, female sex, higher income, solid tumor cancer type, and hormone therapy were significantly associated with higher vaccine uptake, while Hispanic/Latino ethnicity was significantly associated with lower vaccine uptake. In a multivariable model, age (OR 1.18, 95% CI 1.10-1.28; p < 0.001), female sex (OR 1.80, 95% CI 1.22-2.66; p = 0.003), and higher income (OR 1.11, 95% CI 1.01-1.22; p = 0.032), were predictive of COVID-19 vaccine uptake. Conclusions: Overall, vaccine uptake was low among our cohort of previously infected cancer patients. Older age, female sex, and higher income were the only variables associated with COVID-19 vaccine uptake within this vulnerable patient population.

KIT mutations in ocular melanoma: frequency and anatomic distribution.

KIT mutations are known to occur in ~15% of chronic sun damaged cutaneous, mucosal, and acral melanomas. Melanomas with demonstrated activating mutations in KIT or platelet-derived growth factor receptor A (PDGFRA) may benefit from treatment with tyrosine kinase inhibitors. Currently, the limited data regarding KIT mutational status in ocular melanoma suggest that activating mutations are extremely rare. PDGFRA mutational status in ocular melanoma has not been determined. Seventy-five ocular melanomas (53 choroidal, 6 iris, 11 ciliary body, and 5 conjuctival) were selected from the files of the Department of Ophthalmology. High-resolution melting curve analysis and sequencing were performed to detect mutations in KIT exons 9, 11, 13, and 17 and PDGFRA exons 12 and 18. Results of mutational analysis were correlated with anatomical site and KIT (CD117) immunohistochemistry. Eight of 75 (11%) ocular melanomas contained mutations in either the KIT or PDGFRA gene. Five of 53 (9%) choroidal melanomas were associated with mutations (KIT exon 11=3; KIT exon 17=1; PDGFRA intron 18=1). Two of six (33%) iris melanomas and a single (9%) ciliary body melanoma harbored KIT exon 11 mutations. No mutations were identified in conjunctival melanomas. The distribution of KIT and PDGFRA mutations by ocular melanoma anatomical site did not reach statistical significance (P=0.393) CD117 positivity was not predictive of KIT mutational status as only 6 of 58 (10%) CD177-positive tumors harbored KIT mutations. In addition, a KIT exon 17 mutation was identified in one CD117-negative tumor. KIT and PDGFRA mutations do occur in ocular melanomas at a frequency (11%) that is similar to acral and mucosal melanomas. Limited correlation of CD117 positivity with mutational status suggests that all ocular melanomas should undergo mutational analysis to determine if imatinib therapy is appropriate.

Polyester nasal swabs collected in a dry tube are a robust and inexpensive, minimal self-collection kit for SARS-CoV-2 testing.

BACKGROUND: In order to identify an inexpensive yet highly stable SARS-CoV-2 collection device as an alternative to foam swabs stored in transport media, both contrived ("surrogate") CoV-positive and patient-collected spun polyester swabs stored in dry tubes were evaluated for time- and temperature-stability using qPCR. METHODS: Surrogate specimens were prepared by combining multiple, residual SARS-CoV-2-positive clinical specimens and diluting to near-LOD levels in either porcine or human mucus ("matrix"), inoculating foam or polyester nasal swabs, and sealing in dry tubes. Swabs were then subjected to one of three temperature excursions: (1) 4°C for up to 72 hours; (2) 40°C for 12 hours, followed by 32°C for up to 60 hours; or (3) multiple freeze-thaw cycles (-20°C). The stability of extracted SARS-CoV-2 RNA for each condition was evaluated by qPCR. Separate usability studies for the dry polyester swab-based HealthPulse@home COVID-19 Specimen Collection Kit were later conducted in both adult and pediatric populations. RESULTS: Polyester swabs stored dry demonstrated equivalent performance to foam swabs for detection of low and moderate SARS-CoV-2 viral loads. Mimicking warm- and cold- climate shipment, surrogate specimens were stable following either 72 hours of a high-temperature excursion or two freeze-thaw cycles. In addition, usability studies comprised of self-collected patient specimens yielded sufficient material for molecular testing, as demonstrated by RNase P detection. CONCLUSIONS: Polyester nasal swabs stored in dry collection tubes offer a robust and inexpensive self-collection method for SARS-CoV-2 viral load testing, as viral RNA remains stable under conditions required for home collection and shipment to the laboratory.

Molecular control of vertebrate iron homeostasis by iron regulatory proteins.

Both deficiencies and excesses of iron represent major public health problems throughout the world. Understanding the cellular and organismal processes controlling iron homeostasis is critical for identifying iron-related diseases and in advancing the clinical treatments for such disorders of iron metabolism. Iron regulatory proteins (IRPs) 1 and 2 are key regulators of vertebrate iron metabolism. These RNA binding proteins post-transcriptionally control the stability or translation of mRNAs encoding proteins involved in iron homeostasis thereby controlling the uptake, utilization, storage or export of iron. Recent evidence provides insight into how IRPs selectively control the translation or stability of target mRNAs, how IRP RNA binding activity is controlled by iron-dependent and iron-independent effectors, and the pathological consequences of dysregulation of the IRP system.

Comparison of Dual-ISH (DISH) With Fluorescence In Situ Hybridization (FISH) and Correlation With Immunohistochemical Findings for HER2/Neu Status in Breast Carcinoma.

INTRODUCTION: The most widely used methods for determination of HER2/neu status in breast carcinoma are immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). Both techniques are associated with technical and interpretive difficulties. Alternative methods exist including quantitative PCR and the newly developed chromogenic dual in situ hybridization (DISH). METHODS: We evaluated HER2 DISH as an alternative to FISH and report our findings from 101 cases. In addition, we correlated HER2 DISH and FISH results with HercepTest and 4B5 immunohistochemistry. RESULTS: Eight cases failed FISH analysis and none failed DISH analysis. A 95% (88/93) concordance was found between DISH and FISH for all cases in the series. When only 2+ IHC cases were evaluated, the concordance was 94% for DISH and FISH. Using the 2013 ASCO/CAP recommendations, none of the tested cases were equivocal by FISH or DISH despite 66% of cases being 2+ by HercepTest and 32% by the 4B5 antibody. COMMENT: Our study, which utilizes a majority of IHC equivocal cases, demonstrates that HER2 FISH and DISH are concordant methodologies. HER2 DISH is therefore an acceptable alternative to FISH.

Detection of gene rearrangements in targeted clinical next-generation sequencing.

The identification of recurrent gene rearrangements in the clinical laboratory is the cornerstone for risk stratification and treatment decisions in many malignant tumors. Studies have reported that targeted next-generation sequencing assays have the potential to identify such rearrangements; however, their utility in the clinical laboratory is unknown. We examine the sensitivity and specificity of ALK and KMT2A (MLL) rearrangement detection by next-generation sequencing in the clinical laboratory. We analyzed a series of seven ALK rearranged cancers, six KMT2A rearranged leukemias, and 77 ALK/KMT2A rearrangement-negative cancers, previously tested by fluorescence in situ hybridization (FISH). Rearrangement detection was tested using publicly available software tools, including Breakdancer, ClusterFAST, CREST, and Hydra. Using Breakdancer and ClusterFAST, we detected ALK rearrangements in seven of seven FISH-positive cases and KMT2A rearrangements in six of six FISH-positive cases. Among the 77 ALK/KMT2A FISH-negative cases, no false-positive identifications were made by Breakdancer or ClusterFAST. Further, we identified one ALK rearranged case with a noncanonical intron 16 breakpoint, which is likely to affect its response to targeted inhibitors. We report that clinically relevant chromosomal rearrangements can be detected from targeted gene panel-based next-generation sequencing with sensitivity and specificity equivalent to that of FISH while providing finer-scale information and increased efficiency for molecular oncology testing.

Gastrointestinal stromal tumors: clinical significance of p53 expression, MDM2 amplification, and KIT mutation status.

BACKGROUND: Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract. Clinical behavior is best predicted by size and mitotic count (risk index). KIT and platelet-derived growth factor receptor α (PDGFRA) mutations have therapeutic and prognostic value but few other prognostically significant molecular markers have been identified. We investigated the prognostic value of p53 protein expression and MDM2 gene amplification in a series of GISTs. METHODS: Thirty-five GISTs were tested for KIT and PDGFRA mutations, p53 protein expression (high >10% positive by immunohistochemistry) and MDM2 gene amplification (ratio >1.8). Mitotic index (>5/50 HPF), MDM2 amplification status, p53 protein expression, tumor size, and KIT/PDGFRA mutational status were correlated with clinical outcome. RESULTS: Only a single (3%) GIST was amplified for MDM2. p53 protein expression, mitotic index, and KIT/PDGFRA mutations did not correlate with recurrence or metastasis (P=0.20, 0.50, and 0.08, respectively) but tumor size did (P=0.04). Risk assessment (size and mitotic index) showed a weak association with clinical behavior (P=0.19). CONCLUSIONS: MDM2 amplification is uncommon in GISTs. Although high p53 expression occurred in 35% of cases, it did not correlate with clinical behavior. Only GIST size predicted clinical outcome.

Diagnosis of gastrointestinal stromal tumors from minute specimens: cytomorphology, immunohistochemistry, and molecular diagnostic findings.

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal neoplasm arising from the gastrointestinal tract. Workup of these lesions includes morphologic study and immunohistochemical and often molecular diagnostic analysis. Historically, these neoplasms had been included under a number of diagnostic categories including leiomyoma, leiomyosarcoma, schwannoma, and leiomyoblastoma. The lesions that were clearly sarcomatous were difficult to treat and therapeutically refractory to chemotherapeutic agents. Significant progress in our understanding of these neoplasms and our ability to successfully treat them occurred following the discovery that they were immunoreactive for KIT protein and harbored activating mutations in the KIT gene. Many are initially diagnosed by fine-needle aspiration (FNA) but workup may include mutational analysis to help direct therapy. This review outlines a practical approach to the cytologic diagnosis of GISTs and their molecular workup on small specimens obtained by FNA or core biopsy.

MDM2 amplification in malignant peripheral nerve sheath tumors correlates with p53 protein expression.

CONTEXT: MDM2 is known to be abnormally upregulated in a variety of human neoplasms, secondary to gene amplification. Assessment of MDM2 amplification is most useful clinically for separating lipomas (nonamplified) from atypical lipomatous neoplasms or well-differentiated liposarcomas (amplified). MDM2 amplification occurs in approximately 7% of all human neoplasms. In this study, we sought to determine the utility of MDM2 amplification for the separation of benign (schwannomas) and malignant peripheral nerve sheath tumors (MPNSTs). The expression of p53 was correlated with MDM2 amplification because early studies have indicated that MDM2 is rarely amplified in MPNSTs that express p53. OBJECTIVES: To determine the percentage of MPNSTs with MDM2 amplification and the specificity of MDM2 amplification for malignancy in nerve sheath tumors. DESIGN: Fifteen MPNSTs, 14 neurofibromas, and 15 schwannomas were obtained from the files of the Department of Pathology. These cases underwent fluorescent in situ hybridization analysis for the presence of MDM2 amplification. Assessments were also made for cellularity (low or high), percentage of cells staining positively for p53 and MDM2 protein, and percentage of cells staining with MIB-1. RESULTS: Of 15 MPNSTs, 3 (20%) demonstrated amplification of the MDM2 gene. No neurofibromas or schwannomas demonstrated MDM2 amplification. All 3 MDM2 -amplified MPNSTs were positive for p53. Correlation of MDM2 amplification status and p53 immunoreactivity was statistically significant (P  =  .004). CONCLUSIONS: The low frequency (20%) of MDM2 amplification in our series of MPNSTs demonstrates that MDM2 fluorescent in situ hybridization has limited diagnostic value for the separation of benign schwannomas and MPNSTs. Our study demonstrated a positive correlation (P  =  .004) between MDM2 amplification and p53 expression.

Molecular testing in malignant melanoma.

Molecular testing of cancers to determine therapeutic eligibility is now standard of care and has changed the practice of pathology. Recent advances in the treatment of metastatic melanoma with BRAF and KIT inhibitors have increased the demand for molecular testing in melanoma. Furthermore, rapid progress is being made in determining potential new targets, mechanisms of resistance, and developing additional rationally designed therapies. The likely consequence will be a significant expansion of molecular testing for melanoma to include an array of multiple signaling intermediates. Currently, routine testing is mostly limited to BRAF and KIT. Mutations in these genes generally occur in a distinct group of melanoma subsets though, and with the numerous techniques available for mutation analysis, decisions about testing can be complex. The purpose of this review is to provide an overview of clinically relevant mutations which currently guide systemic therapy in Stage IV melanoma, how these molecular events vary with melanoma subtype and primary site of origin, and practical recommendations for testing.

Comparison of reverse transcription-polymerase chain reaction, immunohistochemistry, and fluorescence in situ hybridization methodologies for detection of echinoderm microtubule-associated proteinlike 4-anaplastic lymphoma kinase fusion-positive non-small cell lung carcinoma: implications for optimal clinical testing.

CONTEXT: Echinoderm microtubule-associated proteinlike 4-anaplastic lymphoma kinase (EML4-ALK) gene fusions are detected in 3% to 13% of non-small cell lung carcinomas. Accurate testing for detection of EML4-ALK fusions is essential for appropriate therapy selection. OBJECTIVE: To compare reverse transcription-polymerase chain reaction (RT-PCR), immunohistochemistry (IHC), and fluorescence in situ hybridization (FISH) methodologies for detection of EML4-ALK fusions. DESIGN: Forty-six pulmonary adenocarcinomas were selected with enrichment for wild-type epidermal growth factor receptor (EGFR) status (wild type, n  =  42; mutant, n  =  4). Specimens were tested by IHC (Dako; clone ALK1), FISH (Abbott Molecular; LSI ALK break apart), and RT-PCR (variants 1 and 3a/b). RESULTS: EML4-ALK variant 3a/b was detectable by RT-PCR, FISH, and IHC in 4% (2 of 46) of specimens. Complete agreement among FISH and IHC reviewers was obtained for variant 3a/b. No concordance existed among methodologies for the detection of EML4-ALK variant 1. The RT-PCR method detected variant 1 in 20% (9 of 46) of specimens. Agreement among FISH viewers was poor for variant 1 because only 11% (1/9) of specimens were scored as positive by all 3 viewers. The sensitivity of IHC for detection of variant 1 was also poor because only 1 of 9 samples (11%) was scored as positive. Overall, the frequency of EML4-ALK variants 1 and 3a/b was 24% (11 of 46) in adenocarcinomas enriched for wild-type EGFR status. One EML4-ALK variant 1 fusion was found to coexist with an EGFR exon 21 mutation. CONCLUSIONS: The FISH interpretation demonstrated great variability among observers. The RT-PCR method was the most sensitive and least-subjective methodology for detection of EML4-ALK fusions.

Respiratory cytology in the era of molecular diagnostics: a review.

Carcinoma of the lungs remains one of the primary causes of cancer mortality in the United States and represents a significant diagnostic challenge. Current diagnostic protocols depend substantially on cytology as an initial diagnostic modality. Pulmonary cytology can be diagnostically challenging with false positive and false negative diagnoses being relatively frequent. False positive diagnoses remain a significant problem for the cytologist with benign conditions including reactive atypia of type II pneumocytes, reactive bronchial respiratory epithelium, basal cell hyperplasia, and reactive metaplastic squamous cells being potentially misinterpreted as carcinoma. False negative diagnoses also occur usually attributable to sampling. Traditionally, cytopathologists were expected to recognize carcinoma when present and subdivide it into small cell or nonsmall cell varieties. With the advent of targeted therapy, expectations now include separation of adenocarcinoma from squamous cell carcinoma. Additionally, molecular testing for EGFR mutations and ALK rearrangements is now required as an accompaniment to morphologic diagnosis. This review summarizes the morphologic appearances of the common and diagnostically important carcinomas of the lung and discusses diagnostic pitfalls responsible for false positive and false negative diagnoses. Molecular testing for selection of targeted therapy is also reviewed.

C-KIT and PDGFRA zygosity in gastrointestinal stromal tumors: Correlation with tumor site, tumor size, exon, and CD117 immunohistochemistry.

BACKGROUND: Gastrointestinal stromal tumors (GISTs) often harbor activating mutations in the receptor tyrosine kinases C-KIT or platelet derived growth factor receptor-alpha (PDGFRA). Gain-of-function mutations in these 2 genes, which result in constitutive signaling, are presumed to be dominant and therefore are usually heterozygous. However, homozygous C-KIT mutations have been reported in GISTs, although at varying frequencies in different subsets. METHODS: High-resolution amplicon melting curve analysis and direct sequencing were used to determine the frequency of mutation zygosity in a series of 267 GIST cases with known C-KIT (exons 9, 11, 13 and 17) or PDGFRA (exons 12 and 18) mutations. Mutation zygosity was correlated with clinicopathological characteristics including sex, age, tumor size, tumor location, and C-KIT immunohistochemistry. RESULTS: Forty-two of 267 (15.7%) mutant GISTs were homozygous: 36 in C-KIT exon 11, 1 in C-KIT exon 13, 2 in PDGFRA exon 12, and 3 in PDGFRA exon 18. No correlation was found between mutation zygosity and age, sex, tumor size, or C-KIT expression. Homozygous mutant GISTs from the small intestine were underrepresented (P=0.029) whereas GISTs from metastatic sites such as the liver or pancreas were significantly enriched for mutant homozygosity (P=0.020). CONCLUSIONS: Zygosity of C-KIT or PDGFRA mutations did not correlate with most clinicopathologic features of GISTs including tumor size in our subset. However, homozygous mutant GISTs were associated with metastatic disease.

Utilization of unlabeled probes for the detection of fibroblast growth factor receptor 2 exons 7 and 12 mutations in endometrial carcinoma.

BACKGROUND: Endometrial adenocarcinomas are associated with a variety of molecular abnormalities including microsatellite instability, Kirsten rat sarcoma viral oncogene homolog mutations, and phosphatase and tensin homolog inactivation. Recently, mutations in fibroblast growth factor receptor 2 (FGFR2) have been described but their frequency and clinicopathologic characteristics are incompletely known. METHODS: To determine the frequency of mutations in FGFR2 exons 7 and 12, 43 adenocarcinomas of the endometrium were studied by high-resolution melting analysis utilizing unlabeled probes and sequencing. RESULTS: Three of 43 (7%) endometrial carcinomas harbored FGFR2 exon 7 mutations. All 3 mutations were S252W and occurred in endometrioid (type I) adenocarcinomas. Direct sequencing indicated that 2 of the S252W mutations were heterozygous, whereas 1 was presumably homozygous. No FGFR2 mutations were detected in exon 12. CONCLUSIONS: FGFR2 mutations occur in approximately 7% of adenocarcinomas of the endometrium. Only carcinomas of an endometrioid morphology contain FGFR2 mutations, and in our series all were S252W. FGFR2 exons 7 and 12 unlabeled DNA probes allow for easy screening of endometrial carcinoma for the 2 most common FGFR2 mutations (S252W and N550K). Identification of these mutations may have important implications in directed molecular therapy.

Cysteine oxidation regulates the RNA-binding activity of iron regulatory protein 2.

Iron regulatory protein 2 (IRP2) is an RNA-binding protein that regulates the posttranscriptional expression of proteins required for iron homeostasis such as ferritin and transferrin receptor 1. IRP2 RNA-binding activity is primarily regulated by iron-mediated proteasomal degradation, but studies have suggested that IRP2 RNA binding is also regulated by thiol oxidation. We generated a model of IRP2 bound to RNA and found that two cysteines (C512 and C516) are predicted to lie in the RNA-binding cleft. Site-directed mutagenesis and thiol modification show that, while IRP2 C512 and C516 do not directly interact with RNA, both cysteines are located within the RNA-binding cleft and must be unmodified/reduced for IRP2-RNA interactions. Oxidative stress induced by cellular glucose deprivation reduces the RNA-binding activity of IRP2 but not IRP2-C512S or IRP2-C516S, consistent with the formation of a disulfide bond between IRP2 C512 and C516 during oxidative stress. Decreased IRP2 RNA binding is correlated with reduced transferrin receptor 1 mRNA abundance. These studies provide insight into the structural basis for IRP2-RNA interactions and reveal an iron-independent mechanism for regulating iron homeostasis through the redox regulation of IRP2 cysteines.