Assessing the feasibility of a multimodal liquid biopsy for the diagnosis of HPV-associated oropharyngeal squamous cell carcinoma.

OBJECTIVES: In this feasibility study, we explored the combined use of circulating tumor human papillomavirus (HPV) DNA (ctHPVDNA) and HPV serology as diagnostic tests for HPV-associated oropharyngeal squamous cell carcinoma (OPSCC). METHODS: Among patients with research-banked serum or plasma at diagnosis, IgG antibodies to oncoproteins from HPV types 16, 18, 31, 33, 35, 45, 52, and 58 were detected with multiplex serology. Positivity for HPV 16 was defined based on detection of combinations of anti-E6, E1, E2, and E7 and for other high-risk types on detection of anti-E6 and anti-E7. Circulating tumor HPV DNA was detected by custom digital droplet polymerase chain reaction (ddPCR) assays for HPV types 16, 18, 33, 35, and 45. p16 immunohistochemistry and high-risk HPV RNA in situ hybridization (ISH) using a cocktail of 18 high-risk HPV types were performed on tissue. RESULTS: Of 75 patients, 67 (89.3%) were HPV-associated (p16 and HPV RNA ISH positive) and 8 (10.7%) were HPV-independent. All 8 HPV-independent patients were seronegative and negative for ctHPVDNA (100% specificity). Serology was positive in 53 (79.1%) of 67 HPV-associated patients, while ddPCR was positive for ctHPVDNA in 59 (88.6%) of 67 HPV-associated patients. Requiring both tests to be positive resulted in a sensitivity of 50 (74.6%) of 67 while combining assays (either positive) improved sensitivity to 62 (92.6%) of 67. CONCLUSIONS: Compared to HPV RNA ISH, HPV serology and ctHPVDNA are sensitive and highly specific biomarkers for HPV-associated OPSCC at the time of presentation.

Virtual 3D Specimen Mapping in Head & Neck Oncologic Surgery.

OBJECTIVES: Virtual 3D specimen mapping of oncologic surgical specimens provides a visual record of the specimen and margin sampling sites which can be utilized in a variety of cancer care settings. Our objective was to perform a retrospective review of head and neck surgical oncology cases where the specimen was mapped post-operatively and to evaluate the utility of these 3D specimen maps amongst the multidisciplinary cancer care team. METHODS: A retrospective review of our 3D specimen model biorepository was performed. Surgical specimens were 3D scanned and then graphically annotated (or "mapped") during routine pathologic processing. The resulting 3D specimen maps were distributed to the multidisciplinary oncologic care team. Final margin status and any use of the 3D specimen maps were recorded. RESULTS: A total of 28 cases were included. Virtual 3D specimen maps were utilized by the cancer care team in 8 cases (29%), including 2 positive margin cases, 2 close margin cases, and 4 indeterminate margin cases. 3D specimen maps were used to visualize positive margin sites for pathologist-surgeon communication as a visual reference during tumor board discussions and to inform radiation treatment planning. CONCLUSION: Post-operative virtual 3D specimen mapping of oncologic specimens creates a permanent visual record of the specimen and the margins sampled and may serve as a beneficial tool for communication amongst the multidisciplinary cancer care team. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:191-197, 2024.

Molecular signature incorporating the immune microenvironment enhances thyroid cancer outcome prediction.

Genomic and transcriptomic analysis has furthered our understanding of many tumors. Yet, thyroid cancer management is largely guided by staging and histology, with few molecular prognostic and treatment biomarkers. Here, we utilize a large cohort of 251 patients with 312 samples from two tertiary medical centers and perform DNA/RNA sequencing, spatial transcriptomics, and multiplex immunofluorescence to identify biomarkers of aggressive thyroid malignancy. We identify high-risk mutations and discover a unique molecular signature of aggressive disease, the Molecular Aggression and Prediction (MAP) score, which provides improved prognostication over high-risk mutations alone. The MAP score is enriched for genes involved in epithelial de-differentiation, cellular division, and the tumor microenvironment. The MAP score also identifies aggressive tumors with lymphocyte-rich stroma that may benefit from immunotherapy. Future clinical profiling of the stromal microenvironment of thyroid cancer could improve prognostication, inform immunotherapy, and support development of novel therapeutics for thyroid cancer and other stroma-rich tumors.

Use of nongynecologic cytologic-histologic correlation to identify patterns of error: An institutional experience.

BACKGROUND: Quality management practices empower cytology laboratories to deliver consistent, high-quality patient care. Monitoring of key performance indicators is one way by which laboratories can identify patterns of error and focus their improvement activities. Cytologic-histologic correlation (CHC) identifies error by retrospectively reviewing cytology cases when discordant surgical pathology diagnoses are reported. Analysis of CHC data can elucidate patterns of error and direct quality improvement initiatives. METHODS: CHC data of nongynecologic cytology specimens were reviewed over a 3-year period (2018-2021). Errors were separated by anatomic site and classified as either sampling or interpretive errors. RESULTS: A total of 364 discordant cases were identified out of 4422 cytologic-histologic pairs (a discordant rate of 8%). The majority (272; 75%) were sampling errors, with fewer interpretive errors (92; 25%). Sampling errors were found to occur most commonly in lower urinary tract and lung. Interpretive errors were most commonly found in lower urinary tract and thyroid. CONCLUSIONS: Nongynecologic CHC data can be a valuable resource for cytology laboratories. By studying the types of errors, quality improvement activities can be targeted toward problem areas.

Patterns of Major Frozen Section Interpretation Error: An In-Depth Analysis From a Complex Academic Surgical Pathology Practice.

OBJECTIVES: To establish baseline error rates due to misinterpretation and to identify scenarios in which major errors were most common and potentially preventable. METHODS: Our database was queried over a 3-year period for major discrepancies due to misinterpretation. These were stratified by histomorphologic setting, service, availability/type of prior material, and years of experience and subspecialization of the interpreting pathologist. RESULTS: The overall discordance rate between frozen section (FS) and final diagnoses was 2.9% (199/6,910). Seventy-two errors were due to interpretation, of which 34 (47.2%) were major. Major error rates were highest on the gastrointestinal and thoracic services. Of major discrepancies, 82.4% were rendered in subdisciplines outside those of the FS pathologist. Pathologists with fewer than 10 years' experience made more errors than those with more experience (55.9% vs 23.5%, P = .006). Major error rates were greater for cases without previous material compared to those with a prior glass slide (47.1% vs 17.6%, P = .009). Common histomorphologic scenarios in which disagreements were made involved discriminating mesothelial cells from carcinoma (20.6%) and accurately recognizing squamous carcinoma/severe dysplasia (17.6%). CONCLUSIONS: To improve performance and decrease future misdiagnoses, monitoring discordances should be a continuous component of surgical pathology quality assurance programs.

The effect of the vertical gradients of photosynthetic parameters on the CO2 assimilation and transpiration of a Panamanian tropical forest.

Terrestrial biosphere models (TBMs) include the representation of vertical gradients in leaf traits associated with modeling photosynthesis, respiration, and stomatal conductance. However, model assumptions associated with these gradients have not been tested in complex tropical forest canopies. We compared TBM representation of the vertical gradients of key leaf traits with measurements made in a tropical forest in Panama and then quantified the impact of the observed gradients on simulated canopy-scale CO2 and water fluxes. Comparison between observed and TBM trait gradients showed divergence that impacted canopy-scale simulations of water vapor and CO2 exchange. Notably, the ratio between the dark respiration rate and the maximum carboxylation rate was lower near the ground than at the top-of-canopy, leaf-level water-use efficiency was markedly higher at the top-of-canopy, and the decrease in maximum carboxylation rate from the top-of-canopy to the ground was less than TBM assumptions. The representation of the gradients of leaf traits in TBMs is typically derived from measurements made within-individual plants, or, for some traits, assumed constant due to a lack of experimental data. Our work shows that these assumptions are not representative of the trait gradients observed in species-rich, complex tropical forests.

Sinonasal Adenosquamous Carcinoma - Morphology and Genetic Drivers Including Low- and High-Risk Human Papillomavirus mRNA, DEK::AFF2 Fusion, and MAML2 Rearrangement.

BACKGROUND: Sinonasal adenosquamous carcinoma is rare, and there are almost no studies detailing morphology or characterizing their genetic driver events. Further, many authors have termed sinonasal tumors with combined squamous carcinoma and glands as mucoepidermoid carcinoma but none have analyzed for the presence of MAML2 rearrangement. METHODS: Cases from 2014 to 2020 were collected and diagnosed using World Health Organization criteria. They were tested for p16 expression by immunohistochemistry (70% cut-off), DEK::AFF2 fusion by fluorescence in situ hybridization (FISH) and AFF2 immunohistochemistry, MAML2 rearrangement by FISH, and low- and high-risk HPV by RNA ISH and reverse transcription PCR, respectively. Detailed morphology and clinical features were reviewed. RESULTS: There were 7 male (64%) and 4 female (36%) patients with a median age of 69 years, most Caucasian (10 of 11 or 91%). Most had tobacco exposure (8/11, 73%) and most presented with epistaxis, a visible nasal mass, and/or facial pain. Several had a precursor papillomas (3 of 11, 27%). The squamous component had variable keratinization, 5 of 11 (46%) of which would be described as keratinizing, 3 non-keratinizing, and 2 with mixed features. All had gland formation, by definition, and 2 of 11 (18%) had ciliated tumor cells. None of the 11 cases had MAML2 rearrangement and one had DEK::AFF2 fusion with associated positive nuclear AFF2 protein immunostaining. Most were p16 positive (7 of 11, 64%) and all 7 of these were hrHPV positive either by RNA ISH or RT-PCR. Two of the p16-negative tumors were positive for lrHPV by RNA ISH. Treatment included surgery alone (4 of 11, 36%), surgery with adjuvant radiation (5 of 11, 45%), and surgery with radiation and chemotherapy (2 of 11, 18%). Four of 11 patients (36%) suffered disease recurrence, two requiring re-operation and who were disease free at last follow-up, one receiving additional chemotherapy and who was alive with disease. The other elected to undergo palliative therapy and died of disease. CONCLUSION: Sinonasal adenosquamous carcinoma is a somewhat heterogeneous tumor not infrequently arising ex papilloma and having various drivers including high- and low-risk HPV and rarely DEK::AFF2 fusion. The prognosis appears favorable when proper treatment is possible.

Short-term variation in leaf-level water use efficiency in a tropical forest.

The representation of stomatal regulation of transpiration and CO2 assimilation is key to forecasting terrestrial ecosystem responses to global change. Given its importance in determining the relationship between forest productivity and climate, accurate and mechanistic model representation of the relationship between stomatal conductance (gs ) and assimilation is crucial. We assess possible physiological and mechanistic controls on the estimation of the g1 (stomatal slope, inversely proportional to water use efficiency) and g0 (stomatal intercept) parameters, using diurnal gas exchange surveys and leaf-level response curves of six tropical broadleaf evergreen tree species. g1 estimated from ex situ response curves averaged 50% less than g1 estimated from survey data. While g0 and g1 varied between leaves of different phenological stages, the trend was not consistent among species. We identified a diurnal trend associated with g1 and g0 that significantly improved model projections of diurnal trends in transpiration. The accuracy of modeled gs can be improved by accounting for variation in stomatal behavior across diurnal periods, and between measurement approaches, rather than focusing on phenological variation in stomatal behavior. Additional investigation into the primary mechanisms responsible for diurnal variation in g1 will be required to account for this phenomenon in land-surface models.

Leaves as bottlenecks: The contribution of tree leaves to hydraulic resistance within the soil-plant-atmosphere continuum.

Within vascular plants, the partitioning of hydraulic resistance along the soil-to-leaf continuum affects transpiration and its response to environmental conditions. In trees, the fractional contribution of leaf hydraulic resistance (Rleaf ) to total soil-to-leaf hydraulic resistance (Rtotal ), or fRleaf (=Rleaf /Rtotal ), is thought to be large, but this has not been tested comprehensively. We compiled a multibiome data set of fRleaf using new and previously published measurements of pressure differences within trees in situ. Across 80 samples, fRleaf averaged 0.51 (95% confidence interval [CI] = 0.46-0.57) and it declined with tree height. We also used the allometric relationship between field-based measurements of soil-to-leaf hydraulic conductance and laboratory-based measurements of leaf hydraulic conductance to compute the average fRleaf for 19 tree samples, which was 0.40 (95% CI = 0.29-0.56). The in situ technique produces a more accurate descriptor of fRleaf because it accounts for dynamic leaf hydraulic conductance. Both approaches demonstrate the outsized role of leaves in controlling tree hydrodynamics. A larger fRleaf may help stems from loss of hydraulic conductance. Thus, the decline in fRleaf with tree height would contribute to greater drought vulnerability in taller trees and potentially to their observed disproportionate drought mortality.

The computer-aided design margin: Ex vivo 3D specimen mapping to improve communication between surgeons and pathologists.

BACKGROUND: Numerous challenges exist in determining surgical margin status. Communication between surgeons and pathologists is crucial for specimen orientation and accurate margin assessment. METHODS: A prospective study to determine feasibility of incorporating three-dimensional (3D) scanning into surgical pathology workflow was performed. A structured-light 3D scanner captured the photorealistic surface topography of fresh surgical specimens. Computer-aided design (CAD) software was used to document sites of margin sampling and sectioning. Surveys were distributed among faculty and staff stakeholders to assess feasibility. RESULTS: A series of 40 cases were 3D-scanned. Median image acquisition time was 8 min. The majority of respondents agreed that the experimental 3D system helped achieve clearer communication. 3D specimen maps assisted in the communication of a focally positive or close margin in 4 of 17 cases. CONCLUSIONS: Routine 3D scanning and specimen mapping is feasible and represents an innovative approach to intraoperative and final pathology documentation, margin analysis, and surgeon-pathologist communication.

Enabling FAIR data in Earth and environmental science with community-centric (meta)data reporting formats.

Research can be more transparent and collaborative by using Findable, Accessible, Interoperable, and Reusable (FAIR) principles to publish Earth and environmental science data. Reporting formats-instructions, templates, and tools for consistently formatting data within a discipline-can help make data more accessible and reusable. However, the immense diversity of data types across Earth science disciplines makes development and adoption challenging. Here, we describe 11 community reporting formats for a diverse set of Earth science (meta)data including cross-domain metadata (dataset metadata, location metadata, sample metadata), file-formatting guidelines (file-level metadata, CSV files, terrestrial model data archiving), and domain-specific reporting formats for some biological, geochemical, and hydrological data (amplicon abundance tables, leaf-level gas exchange, soil respiration, water and sediment chemistry, sensor-based hydrologic measurements). More broadly, we provide guidelines that communities can use to create new (meta)data formats that integrate with their scientific workflows. Such reporting formats have the potential to accelerate scientific discovery and predictions by making it easier for data contributors to provide (meta)data that are more interoperable and reusable.

Sinonasal Bacteroma/Bacteria-related Concretions: A Distinct Pathologic Entity of the Sinonasal Tract.

Patients can be seen where "fungal debris," "mycetoma," or "mass-like obstruction" of the sinonasal tract is suspected clinically but lack fungus and instead have granular, eosinophilic debris and bacterial colonies. We report and characterize 15 such cases, tentatively termed "bacteromas," compared with randomly selected cases of mycetoma and allergic fungal sinusitis (AFS). Pathology reports from 2016 to 2021 were searched. All candidate cases were examined microscopically and included if they had granular, amorphous debris with negative Grocott methenamine silver staining and lacked diagnostic features of other entities. The 7 males and 8 females ranged from 21 to 78 years old. Imaging frequently revealed opacification of the paranasal sinuses. Operative reports showed all to have paranasal sinus involvement. Most were unilateral (13/15, 87%). The maxillary sinus was involved in 11/15 (73%) cases, sphenoid sinus in 2/15 (13%), and frontal and ethmoid sinuses in 1/15 (7%), each. Bacteroma patients frequently had a history of allergic rhinitis (8/15, 53%), more than mycetomas (1/15, 7%) and AFS (5/15, 33%) ( P =0.0142). Facial pain was a common presenting symptom (13/15, 87%) in bacteromas compared with mycetomas (5/15, 33%) or AFS (1/15, 7%). Morphologically, cases consisted of large aggregates of paucicellular to acellular debris with a characteristic densely eosinophilic granular appearance, commonly associated with bacteria. Four of the 10 cultured patients grew Pseudomonas aeruginosa . Course posttreatment ranged from symptom resolution 1 week postoperatively to recurrent infections and symptoms 23 months from the initial operation. In summary, "bacteroma" is a heretofore undescribed pathologic entity of the sinuses that appears to be related to chronic bacterial infection and is distinct from mycetoma, AFS, and rhinolithiasis.

CD163 Immunohistochemical "Circle Sign" Staining Pattern Differentiates Sinonasal Papillomas From Morphologically Similar Non-neoplastic Lesions.

Sinonasal papillomas are a diverse group of benign epithelial neoplasms of the sinonasal tract. Inverted papilloma, in particular, must be distinguished from other lesions with no malignant potential. The aim of this study was to distinguish sinonasal papillomas from morphologically similar lesions using CD163 immunostaining. Cases from a 19-year period were identified. These included 49 inverted, 10 exophytic, and 12 oncocytic papillomas, 21 chronic sinusitides with squamous metaplasia, 27 inflammatory polyps, 5 verrucae vulgares, 5 respiratory epithelial adenomatoid hamartomas, and 6 DEK::AFF2 carcinomas of the sinonasal tract. A subset of biopsy cases (8 inverted papillomas, 5 inflammatory polyps) was separately analyzed. CD163 immunohistochemistry (IHC) was performed. A unique "circle" staining pattern was identified in the surface epithelium. After locating a hotspot, circles were quantified in 10 consecutive high-power fields. Circles were present in 66/71 (93%) cases of sinonasal papilloma, with a mean of 35 circles/10 HPF (range: 0 to 160/10 HPF) and a median of 19 circles/10 HPF. Circles were present in 20/58 (34%) non-neoplastic cases, with a mean of 2 circles/10 HPF (range: 0 to 27/10 HPF) and a median of 0. Considering all resection and biopsy cases, performance for distinguishing papillomas from non-neoplastic lesions was best at a cutoff of 10 circles/10 HPF (2-tailed P <0.0001) with sensitivity, specificity, positive predictive value, and negative predictive value of 66.2%, 93.1%, 92.1%, and 69.2%, respectively. The results were similar in the biopsy subset. One other neoplastic entity, the DEK::AFF2 carcinomas, also showed prominent CD163 circle staining. In summary, sinonasal papillomas demonstrate extensive CD163 "circle" staining in the epithelium compared with the non-neoplastic lesions studied. As such, the "circle sign" on CD163 IHC may be helpful in distinguishing between diagnoses, particularly on small biopsies or equivocal specimens.

Cytology and LGBT+ health: establishing inclusive cancer screening programs.

There are substantial disparities in cancer screening for sexual minorities and gender non-conforming patients. In additional to patients having trauma due to negative experiences with the healthcare system, disparities may be heightened due to heteronormative and cisnormative design of screening programs and electronic medical record systems. Furthermore, there are morphologic challenges specific to certain specimen types from the LGBT + population, such as anal cytology samples, cervical cytology from transgender men taking testosterone, and neovaginal cytology samples. Men who have sex with men are at increased risk for anal cancer compared with the general population. While early detection of anal dysplasia decreases the risk of invasive carcinoma, screening programs are not widespread. Cervical cancer screening may be psychologically and physically challenging for transgender men and non-binary patients. The use of exogenous testosterone therapy causes atrophic changes in cervical cytology samples which mimic high-grade dysplasia. The rate of unsatisfactory samples are also increased in this population. Although HPV driven cancers have been reported in patients with neovaginas, there are currently no guidelines about appropriate screening for transgender women and intersex patients who have neovaginas. Cytopathologists can optimize the health of LGBT + patients in many ways including advocating for inclusive screening guidelines, validating self-collection for HPV and cytology samples, updating requisition forms to better capture the spectrum of gender expression, and recognizing the morphologic changes in cytology samples due to exogenous hormone use.

Diagnostic Value of MAML2 Rearrangements in Mucoepidermoid Carcinoma.

Mucoepidermoid carcinoma (MEC) is often seen in salivary glands and can harbor MAML2 translocations (MAML2+). The translocation status has diagnostic utility as an objective confirmation of the MEC diagnosis, for example, when distinction from the more aggressive adenosquamous carcinoma (ASC) is not straightforward. To assess the diagnostic relevance of MAML2, we examined our 5-year experience in prospective testing of 8106 solid tumors using RNA-seq panel testing in combinations with a two-round Delphi-based scenario survey. The prevalence of MAML2+ across all tumors was 0.28% (n = 23/8106) and the majority of MAML2+ cases were found in head and neck tumors (78.3%), where the overall prevalence was 5.9% (n = 18/307). The sensitivity of MAML2 for MEC was 60% and most cases (80%) were submitted for diagnostic confirmation; in 24% of cases, the MAML2 results changed the working diagnosis. An independent survey of 15 experts showed relative importance indexes of 0.8 and 0.65 for "confirmatory MAML2 testing" in suspected MEC and ASC, respectively. Real-world evidence confirmed that the added value of MAML2 is a composite of an imperfect confirmation test for MEC and a highly specific exclusion tool for the diagnosis of ASC. Real-world evidence can help move a rare molecular-genetic biomarker from an emerging tool to the clinic.

Nondiagnostic category of Milan System for Reporting Pediatric Salivary Gland Cytopathology: outcomes and root cause analysis.

BACKGROUND: Fine-needle aspiration (FNA) results classified as the nondiagnostic category of the Milan system for reporting salivary gland cytopathology (MSRSGC) may be infrequently encountered in children. Clinical management may be challenging due to lack of data regarding outcomes and underlying causes. METHODS: We retrospectively analyzed 106 consecutive pediatric salivary gland FNAs (2000-2020; 45% performed under image guidance). The outcomes of patients with nondiagnostic results were analyzed. Clinical parameters, FNA procedural parameters, and histopathologic parameters were compared between diagnostic and nondiagnostic cases. A root cause analysis was performed using the fishbone diagram and the 5 Whys method. RESULTS: A total of 103 initial FNAs were identified. The nondiagnostic rates for initial and repeat biopsy were 16% (16/103) and 67% (2/3), respectively. Initial nondiagnostic FNAs were most frequently managed by clinical/radiologic follow-up only (56%, 9/16), followed by direct surgery (19%, 3/16) and repeat FNA (19%, 3/16). By histologic and clinical/radiologic follow-up, the risk of malignancy for nondiagnostic cases was zero. Palpation guidance (P < .05), inadequate sampling determined by rapid on-site evaluation (P < .01), and lesions with cystic, vascular, or diffuse nature (P < .05) were significantly associated with nondiagnostic results. By root cause analysis, proceduralist sampling error and lack of ultrasound guidance were the most common primary and secondary causes, respectively. CONCLUSIONS: Pediatric salivary gland lesions of the nondiagnostic MSRSGC category have minimal risk of malignancy and may be successfully managed by clinical/radiologic follow-up. The root causes for nondiagnostic results were often multifactorial and primarily related to proceduralist sampling, characteristics of the lesions, and lack of ultrasound guidance.

Fine-Needle Aspiration Biopsy of Pediatric Salivary Gland Tumors: Analysis of Patient Tolerability, Sedation Requirement, and Procedural Complication.

OBJECTIVE: Fine-needle aspiration (FNA) biopsy is the standard diagnostic tool recommended by consensus management guidelines for preoperative evaluation of salivary gland tumors in adults. However, its utility in the pediatric population remains debated due to a paucity of data and inherited challenges of pediatric management (patient cooperation, the need for sedation, and procedural complications). METHODS: Consecutive series of 92 FNA biopsies of pediatric salivary gland lesions with available procedural data were included for retrospective analysis. Patient demographics, procedural characteristics, and complications were assessed. RESULTS: Sixty-three patients (68%) tolerated FNA without sedation. Sedation need was significantly associated with younger age, concurrent non-FNA procedure requiring sedation, ultrasound guidance, interventional radiologist as the proceduralist, and radiology suite as the facility setting. The sedation rates for children, and early, middle, and late adolescents were 69%, 32%, 12%, and 10%, respectively, with an optimal cutoff point of ≤12 years for age derived from receiver operating characteristic curve analysis. No significant procedural complications were observed. Sedation did not provide significantly better diagnostic yield. CONCLUSION: FNA biopsy of salivary gland tumors is safe, well tolerated by the pediatric population, and can be effectively performed in an outpatient setting without sedation in most cases. FNA biopsy is a useful tool in the preoperative management of pediatric patients with salivary gland tumors.

An improved representation of the relationship between photosynthesis and stomatal conductance leads to more stable estimation of conductance parameters and improves the goodness-of-fit across diverse data sets.

Stomata play a central role in surface-atmosphere exchange by controlling the flux of water and CO2 between the leaf and the atmosphere. Representation of stomatal conductance (gsw ) is therefore an essential component of models that seek to simulate water and CO2 exchange in plants and ecosystems. For given environmental conditions at the leaf surface (CO2 concentration and vapor pressure deficit or relative humidity), models typically assume a linear relationship between gsw and photosynthetic CO2 assimilation (A). However, measurement of leaf-level gsw response curves to changes in A are rare, particularly in the tropics, resulting in only limited data to evaluate this key assumption. Here, we measured the response of gsw and A to irradiance in six tropical species at different leaf phenological stages. We showed that the relationship between gsw and A was not linear, challenging the key assumption upon which optimality theory is based-that the marginal cost of water gain is constant. Our data showed that increasing A resulted in a small increase in gsw at low irradiance, but a much larger increase at high irradiance. We reformulated the popular Unified Stomatal Optimization (USO) model to account for this phenomenon and to enable consistent estimation of the key conductance parameters g0 and g1 . Our modification of the USO model improved the goodness-of-fit and reduced bias, enabling robust estimation of conductance parameters at any irradiance. In addition, our modification revealed previously undetectable relationships between the stomatal slope parameter g1 and other leaf traits. We also observed nonlinear behavior between A and gsw in independent data sets that included data collected from attached and detached leaves, and from plants grown at elevated CO2 concentration. We propose that this empirical modification of the USO model can improve the measurement of gsw parameters and the estimation of plant and ecosystem-scale water and CO2  fluxes.

SALL-4 and Beta-Catenin Expression in Sinonasal Teratocarcinosarcoma.

Sinonasal teratocarcinosarcoma (SNTCS) is a rare, aggressive malignancy that displays a heterogeneous combination of malignant blastema-like, epithelial and mesenchymal components. Its exact histogenesis is unknown with hypotheses ranging from true germ cell derivation to origin from pluripotent stem cells. However, despite this tumor's multiphenotypic histology, which includes frequent glandular, squamous, and neuroectodermal differentiation similar to adnexal germ cell tumors, SNTCS appears to have some differences from adnexal teratomas. For example, unlike adnexal teratomas, SNTCS has never been described as a component in a mixed germ cell tumor. Accurate recognition of SNTCS is difficult due to its rarity and histologic overlap with other sinonasal tumors. It is even more problematic on biopsy, since not all elements may be present in small samples. SNTCS can also share similar staining patterns with other neoplasms in the differential diagnosis. A recent study found nuclear ß-catenin expression in a single TCS, but this has yet to be confirmed in additional cases. SALL-4, a marker of germ cell tumors, has not been examined. We performed ß-catenin and SALL-4 immunohistochemistry on whole sections of 7 SNTCS and 19 other sinonasal neoplasms to assess whether ß-catenin and SALL-4 are of utility in establishing a diagnosis of SNTCS. Intensity of expression and percentage of staining was noted for each tumor. For SNTCS, distribution of staining within each histologic component (immature neuroectodermal, epithelial, and mesenchymal) was also documented. Nuclear ß-catenin expression was not identified in any SNTCS, with all cases demonstrating membranous expression (6 cases) or cytoplasmic and membranous expression (1 case). SALL-4 immunohistochemistry, however, was relatively sensitive (85.7%) and specific (89.5%) for SNTCS. SALL-4 expression was also identified in one poorly differentiated neuroendocrine carcinoma and one case of sinonasal undifferentiated carcinoma. SALL-4 appears to have utility in distinguishing SNTCS from other high grade sinonasal tumors.