Ecological factors and parity mode correlate with genome size variation in squamate reptiles

BACKGROUND

Evidence of correlation between genome size, the nuclear haploid DNA content of a cell, environmental factors and life-history traits have been reported in many animal species. Genome size, however, spans over three orders of magnitude across taxa and such a correlation does not seem to follow a universal pattern. In squamate reptiles, the second most species-rich order of vertebrates, there are currently no studies investigating drivers of genome size variability. We run a series of phylogenetic generalized least-squares models on 227 species of squamates to test for possible relationships between genome size and ecological factors including latitudinal distribution, bioclimatic variables and microhabitat use. We also tested whether genome size variation can be associated with parity mode, a highly variable life history trait in this order of reptiles.

RESULTS

The best-fitting model showed that the interaction between microhabitat use and parity mode mainly accounted for genome size variation. Larger genome sizes were found in live-bearing species that live in rock/sand ecosystems and in egg-laying arboreal taxa. On the other hand, smaller genomes were found in fossorial live-bearing species.

CONCLUSIONS

Environmental factors and species parity mode appear to be among the main parameters explaining genome size variation in squamates. Our results suggest that genome size may favour adaptation of some species to certain environments or could otherwise result from the interaction between environmental factors and parity mode. Integration of genome size and genome sequencing data could help understand the role of differential genome content in the evolutionary process of genome size variation in squamates.

Species-specific gill's microbiome of eight crab species with different breathing adaptations

Transitions to physically different environments, such as the water-to-land transition, proved to be the main drivers of relevant evolutionary events. Brachyuran crabs evolved remarkable morphological, behavioral, and physiological adaptations to terrestrial life. Terrestrial species evolved new respiratory structures devoted to replace or support the gills, a multifunctional organ devoted to gas exchanges, ion-regulation and nitrogen excretion. It was hypothesized that microorganisms associated with respiratory apparatus could have facilitated the processes of osmoregulation, respiration, and elimination of metabolites along this evolutionary transition. To test if crab species with different breathing adaptations may host similar microbial communities on their gills, we performed a comparative targeted-metagenomic analysis, selecting two marine and six terrestrial crabs belonging to different families and characterised by different breathing adaptations. We analysed anterior and posterior gills separately according to their different and specific roles. Regardless of their terrestrial or marine adaptations, microbial assemblages were strongly species-specific indicating a non-random association between the host and its microbiome. Significant differences were found in only two terrestrial species when considering posterior vs. anterior gills, without any association with species-specific respiratory adaptations. Our results suggest that all the selected species are strongly adapted to the ecological niche and specific micro-habitat they colonise.

Reinforcing the idea of an early dispersal of Hippopotamus amphibius in Europe: Restoration and multidisciplinary study of the skull from the Middle Pleistocene of Cava Montanari (Rome, central Italy)

A skull of Hippopotamus recovered from the area of Tor di Quinto, within the urban area of Rome (central Italy) is here redescribed. Despite being one of the most complete specimens of hippopotamuses of the European Pleistocene, the Tor di Quinto skull did not attract much research interest, due to long-standing uncertainties on its provenance. This work begun in 2021, when the skull was restored, within a large renovation project on the vertebrate exposed at the Earth Science University Museum of Sapienza University of Rome. Original sediments were found inside the cranial and mandible cavities during the restoration work, which were sampled for petrographic analyses. By combining a review of the old paleontological, archeological and geological literature published during the 19th and 20th century on the Rome basin and the correlation of these new sedimentological and petrographic information with the lithostratigraphic and synthemic units of the national geological cartography, we clarify that the Hippopotamus skull was most likely to have been collected from a quarry called Cava Montanari, from a formation dated between 560 and 460 ka. Morphological and biometric analyses clearly support an attribution of the Cava Montanari specimen to the extant species Hippopotamus amphibius. The reassessment of the stratigraphic and geological data on Cava Montanari implies that the studied specimen is the earliest confirmed occurrence of Hippopotamus amphibius in the European fossil record.

Chemosensory proteins as putative semiochemical carriers in the desert isopod Hemilepistus reaumurii

The order Isopoda contains both aquatic and terrestrial species, among which Hemilepistus reaumurii, which lives in arid environments and is the most adapted to terrestrial life. Olfaction has been deeply investigated in insects while it has received very limited attention in other arthropods, particularly in terrestrial crustaceans. In insects, soluble proteins belonging to two main families, Odorant Binding Proteins (OBPs) and Chemosensory Proteins (CSPs), are contained in the olfactory sensillar lymph and are suggested to act as carriers of hydrophobic semiochemicals to or from membrane-bound olfactory receptors. Other protein families, namely Nieman-Pick type 2 (NPC2) and Lipocalins (LCNs) have been also reported as putative odorant carriers in insects and other arthropod clades. In this study, we have sequenced and analysed the transcriptomes of antennae and of the first pair of legs of H. reaumurii focusing on soluble olfactory proteins. Interestingly, we have found 13 genes encoding CSPs, whose sequences differ from those of the other arthropod clades, including non-isopod crustaceans, for the presence of two additional cysteine residues, besides the four conserved ones. Binding assays on two of these proteins showed strong affinities for fatty acids and long-chain unsaturated esters and aldehydes, putative semiochemicals for this species.

Conserved organ-specific microbial assemblages in different populations of a terrestrial crab

Microorganisms are ubiquitous in the environment and provide genetic and physiological functions to multicellular organisms. Knowledge on the associated microbiota is becoming highly relevant to understand the host's ecology and biology. Among invertebrates, many examples of endosymbiosis have been described, such as those in corals, ants, and termites. At present, however, little is known on the presence, diversity, and putative roles of the microbiota associated to brachyuran crabs in relation to their environment. In this work we investigated the associated microbiota of three populations of the terrestrial brachyuran crab Chiromantes haematocheir to find evidence of a conserved organ-specific microbiome unrelated to the population of origin and dissimilar from environmental microbial assemblages. Bacterial 16S rRNA gene and fungal ITS sequences were obtained from selected crab organs and environmental matrices to profile microbial communities. Despite the presence of truly marine larval stages and the absence of a gregarious behaviour, favouring microbiota exchanges, we found common, organ-specific microbiota, associated with the gut and the gills of crabs from the different populations (with more than 15% of the genera detected specifically enriched only in one organ). These findings suggest the presence of possible functional roles of the organ-specific microbiota.

A high-quality reference genome for the critically endangered Aeolian wall lizard, Podarcis raffonei

The Aeolian wall lizard, Podarcis raffonei, is an endangered species endemic to the Aeolian archipelago, Italy, where it is present only in three tiny islets and a narrow promontory of a larger island. Because of the extremely limited area of occupancy, severe population fragmentation and observed decline, it has been classified as Critically Endangered by the International Union for the Conservation of Nature (IUCN). Using Pacific Biosciences (PacBio) High Fidelity (HiFi) long read sequencing, Bionano optical mapping and Arima chromatin conformation capture sequencing (Hi-C), we produced a high-quality, chromosome-scale reference genome for the Aeolian wall lizard, including Z and W sexual chromosomes. The final assembly spans 1.51 Gb across 28 scaffolds with a contig N50 of 61.4 Mb, a scaffold N50 of 93.6 Mb, and a BUSCO completeness score of 97.3%. This genome constitutes a valuable resource for the species to guide potential conservation efforts and more generally for the squamate reptiles that are underrepresented in terms of available high-quality genomic resources.

A chromosome-level reference genome and pangenome for barn swallow population genomics

Insights into the evolution of non-model organisms are limited by the lack of reference genomes of high accuracy, completeness, and contiguity. Here, we present a chromosome-level, karyotype-validated reference genome and pangenome for the barn swallow (Hirundo rustica). We complement these resources with a reference-free multialignment of the reference genome with other bird genomes and with the most comprehensive catalog of genetic markers for the barn swallow. We identify potentially conserved and accelerated genes using the multialignment and estimate genome-wide linkage disequilibrium using the catalog. We use the pangenome to infer core and accessory genes and to detect variants using it as a reference. Overall, these resources will foster population genomics studies in the barn swallow, enable detection of candidate genes in comparative genomics studies, and help reduce bias toward a single reference genome.

A multidisciplinary integrated approach using Pachygrapsus marmoratus to assess the impact of port activities on mediterranean marine protected areas

The establishment of marine protected areas is considered the main global strategy to halt the loss of marine biodiversity. Since most of marine areas are open systems, this form of habitat protection cannot prevent their contamination due to human activities performed outside of their borders. Innovative approaches to assess the health status of protected marine habitats are therefore needed. Here we developed a multidisciplinary approach that combines ecological characteristics, bioaccumulation of inorganic and organic pollutants, cell damage (micronuclei frequency, nuclear alterations and LPO) and enzymatic (AChE, CAT, IDH, LDH, GST and CAT) markers focused on an intertidal brachyuran crab, Pachygrapsus marmoratus, to assess the impacts of contaminant exposure on Mediterranean coastal habitats. As study sites we selected two protected areas and two sites within industrial ports of the Ligurian Sea. Our results showed that the selected crab species is an excellent bioindicator. Individuals collected in sites with the highest levels of heavy metal pollution showed the highest signals of stress responses at both cellular and enzymatic levels, coupled with a high incidence of the parasite Sacculina carcini, a signal of impairment of their standard development and reproduction cycle. We could also prove that one of the selected marine protected areas showed the same intensity of impact as its adjacent port site. Our multidisciplinary approach proved to be a valuable tool to assess the environmental quality and health of protected and disturbed Mediterranean coastal environments and to inform efficient management and protection schemes for such habitats.

Stratigraphic reassessment of Grotta Romanelli sheds light on Middle-Late Pleistocene palaeoenvironments and human settling in the Mediterranean

During the last century, Grotta Romanelli (Southern Italy) has been a reference site for the European Late Pleistocene stratigraphy, due to its geomorphological setting and archaeological and palaeontological content. The beginning of the sedimentation inside the cave was attributed to the Last Interglacial (MISs 5e) and the oldest unearthed evidence of human occupation, including remains of hearths, was therefore referred to the Middle Palaeolithic. Recent surveys and excavations produced new U/Th dates, palaeoenvironmental interpretation and a litho-, morpho- and chrono-stratigraphical reassessment, placing the oldest human frequentation of the cave between MIS 9 and MIS 7, therefore embracing Glacial and Interglacial cycles. These new data provide evidence that the sea reached the cave during the Middle Pleistocene and human occupation occurred long before MISs 5e and persisted beyond the Pleistocene- Holocene boundary.

Ecological, physiological and life-history traits correlate with genome sizes in decapod crustaceans

Crustaceans are characterized by some of the most variable genome sizes among animals. Significant relationships between genome size and specific eco-physiological and morphological features have been described in many crustacean taxa, such as Amphipoda, Ostracoda, Cladocera, and Copepoda. A consistent pattern of genome size variation is yet to be found, however, in one of the most specious order of crustaceans, the Decapoda. We investigated how genome size is related to selected eco-physiological and life-history traits in species belonging to this order. We analyzed the respiratory, excretory, and developmental adaptations of 179 decapod species inhabiting shallow marine, deep marine, freshwater, intertidal, and terrestrial habitats. Our results show that the genome size is significantly larger in decapods that have a direct development. Moreover, in Anomura, Astacidea, and Brachyura we found larger genome sizes in species (i) living in freshwater habitats, (ii) using gills as a strictly water-breathing organs, and (iii) presenting a direct development. While species that (i) live in shallow waters, and intertidal and terrestrial habitats, (ii) have some degrees of air-breathing adaptations, namely gills that can exchange oxygen with air if wet or branchiostegal lungs, and (iii) possess an indirect or extended development are characterized by significantly smaller genomes. Our analyses show that developmental complexity affects genome size in decapods, and that multiple eco-physiological and life-history traits correlate with genome size in Anomura, Astacidea, and Brachyura.

Population structure, genomic diversity and demographic history of Komodo dragons inferred from whole-genome sequencing

Population and conservation genetics studies have greatly benefited from the development of new techniques and bioinformatic tools associated with next-generation sequencing. Analysis of extensive data sets from whole-genome sequencing of even a few individuals allows the detection of patterns of fine-scale population structure and detailed reconstruction of demographic dynamics through time. In this study, we investigated the population structure, genomic diversity and demographic history of the Komodo dragon (Varanus komodoensis), the world's largest lizard, by sequencing the whole genomes of 24 individuals from the five main Indonesian islands comprising the entire range of the species. Three main genomic groups were observed. The populations of the Island of Komodo and the northern coast of Flores, in particular, were identified as two distinct conservation units. Degrees of genomic divergence among island populations were interpreted as a result of changes in sea level affecting connectivity across islands. Demographic inference suggested that Komodo dragons probably experienced a relatively steep population decline over the last million years, reaching a relatively stable N_e during the Saalian glacial cycle (400-150 thousand years ago) followed by a rapid N_e decrease. Genomic diversity of Komodo dragons was similar to that found in endangered or already extinct reptile species. Overall, this study provides an example of how whole-genome analysis of a few individuals per population can help define population structure and intraspecific demographic dynamics. This is particularly important when applying population genomics data to conservation of rare or elusive endangered species.

A DNA barcode library for mangrove gastropods and crabs of Hong Kong and the Greater Bay Area reveals an unexpected faunal diversity associated with the intertidal forests of Southern China

Background

Mangroves are tropical and subtropical intertidal forests colonising sheltered coasts across the world. They host a unique faunal community, dominated by brachyuran crabs and gastropods. These invertebrates strongly contribute to the functionality of the entire forest. The reliable assessment of mangrove faunal diversity is, thus, a crucial step for efficient management and conservation plans, but it is hindered by difficulties in species identification. Here we provide a verified DNA barcode library for brachyuran crabs and gastropods inhabiting the mangroves of the Greater Bay Area, Southern China. In particular, we collected and morphologically identified 1100 specimens of mangrove associated brachyuran crabs and gastropods. The partial sequences of the mtDNA cytochrome oxidase subunit I gene were obtained from 275 specimens. Barcode sequences were then used to delineate Molecular Operational Taxonomic Units (MOTUs), employing three different delimitation methods: the automatic barcode gap discovery (ABGD) method, the general mixed Yule coalescent (GMYC) model and a Bayesian implementation of the Poisson tree processes (bPTP) model.

Results

By integrating DNA barcodes with morphology, we identified 44 gastropod species and 58 brachyuran species associated with Hong Kong mangroves, with five and seven new records, for gastropods and crabs, respectively, for the Greater Bay Area. The delineation of MOTUs based on barcode sequences revealed a strong congruence between morphological and molecular identification for both taxa, showing the high reliability of the barcode library.

Conclusions

This study provides the first reference barcode library for mangrove-associated macrobenthic fauna in the Greater Bay Area and represents a reliable tool to management and conservation plans. Our molecular analyses resolved long lasting taxonomic misidentifications and inconsistencies and updated the knowledge on the geographical distribution of Asian mangrove associated fauna, ultimately highlighting a level of biodiversity higher than previously thought for Southern China.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12862-021-01914-6.

Lipocalins in Arthropod Chemical Communication

Lipocalins represent one of the most successful superfamilies of proteins. Most of them are extracellular carriers for hydrophobic ligands across aqueous media, but other functions have been reported. They are present in most living organisms including bacteria. In animals they have been identified in mammals, molluscs, and arthropods; sequences have also been reported for plants. A subgroup of lipocalins, referred to as odorant-binding proteins (OBPs), mediate chemical communication in mammals by ferrying specific pheromones to the vomeronasal organ. So far, these proteins have not been reported as carriers of semiochemicals in other living organisms; instead chemical communication in arthropods is mediated by other protein families structurally unrelated to lipocalins. A search in the databases has revealed extensive duplication and differentiation of lipocalin genes in some species of insects, crustaceans, and chelicerates. Their large numbers, ranging from a handful to few dozens in the same species, their wide divergence, both within and between species, and their expression in chemosensory organs suggest that such expansion may have occurred under environmental pressure, thus supporting the hypothesis that lipocalins may be involved in chemical communication in arthropods.

Bridging the Gap between Vertebrate Cytogenetics and Genomics with Single-Chromosome Sequencing (ChromSeq)

The study of vertebrate genome evolution is currently facing a revolution, brought about by next generation sequencing technologies that allow researchers to produce nearly complete and error-free genome assemblies. Novel approaches however do not always provide a direct link with information on vertebrate genome evolution gained from cytogenetic approaches. It is useful to preserve and link cytogenetic data with novel genomic discoveries. Sequencing of DNA from single isolated chromosomes (ChromSeq) is an elegant approach to determine the chromosome content and assign genome assemblies to chromosomes, thus bridging the gap between cytogenetics and genomics. The aim of this paper is to describe how ChromSeq can support the study of vertebrate genome evolution and how it can help link cytogenetic and genomic data. We show key examples of ChromSeq application in the refinement of vertebrate genome assemblies and in the study of vertebrate chromosome and karyotype evolution. We also provide a general overview of the approach and a concrete example of genome refinement using this method in the species Anolis carolinensis.

To the Land and Beyond: Crab Microbiomes as a Paradigm for the Evolution of Terrestrialization

The transition to terrestrial environments by formerly aquatic species has occurred repeatedly in many animal phyla and lead to the vast diversity of extant terrestrial species. The differences between aquatic and terrestrial habitats are enormous and involved remarkable morphological and physiological changes. Convergent evolution of various traits is evident among phylogenetically distant taxa, but almost no information is available about the role of symbiotic microbiota in such transition. Here, we suggest that intertidal and terrestrial brachyuran crabs are a perfect model to study the evolutionary pathways and the ecological role of animal-microbiome symbioses, since their transition to land is happening right now, through a number of independent lineages. The microorganisms colonizing the gut of intertidal and terrestrial crabs are expected to play a major role to conquer the land, by reducing water losses and permitting the utilization of novel food sources. Indeed, it has been shown that the microbiomes hosted in the digestive system of terrestrial isopods has been critical to digest plant items, but nothing is known about the microbiomes present in the gut of truly terrestrial crabs. Other important physiological regulations that could be facilitated by microbiomes are nitrogen excretion and osmoregulation in the new environment. We also advocate for advances in comparative and functional genomics to uncover physiological aspects of these ongoing evolutionary processes. We think that the multidisciplinary study of microorganisms associated with terrestrial crabs will shed a completely new light on the biological and physiological processes involved in the sea-land transition.

Investigation of mechanisms underlying chaotic genetic patchiness in the intertidal marbled crab Pachygrapsus marmoratus (Brachyura: Grapsidae) across the Ligurian Sea

Background

Studies on marine community dynamics and population structures are limited by the lack of exhaustive knowledge on the larval dispersal component of connectivity. Genetic data represents a powerful tool in understanding such processes in the marine realm. When dealing with dispersion and connectivity in marine ecosystems, many evidences show patterns of genetic structure that cannot be explained by any clear geographic trend and may show temporal instability. This scenario is usually referred to as chaotic genetic patchiness, whose driving mechanisms are recognized to be selection, temporal shifts in local population dynamics, sweepstakes reproductive success and collective dispersal.

In this study we focused on the marbled crab Pachygrapsus marmoratus that inhabits the rocky shores of the Mediterranean Sea, Black Sea and East Atlantic Ocean, and disperses through planktonic larvae for about 1 month. P. marmoratus exhibits unexpectedly low connectivity levels at local scale, although well-defined phylogeographic patterns across the species’ distribution range were described. This has been explained as an effect of subtle geographic barriers or due to sweepstake reproductive success. In order to verify a chaotic genetic patchiness scenario, and to explore mechanisms underlying it, we planned our investigation within the Ligurian Sea, an isolated basin of the western Mediterranean Sea, and we genotyped 321 individuals at 11 microsatellite loci.

Results

We recorded genetic heterogeneity among our Ligurian Sea samples with the occurrence of genetic clusters not matching the original populations and a slight inter-population divergence, with the geographically most distant populations being the genetically most similar ones. Moreover, individuals from each site were assigned to all the genetic clusters. We also recorded evidences of self-recruitment and a higher than expected within-site kinship.

Conclusions

Overall, our results suggest that the chaotic genetic patchiness we found in P. marmoratus Ligurian Sea populations is the result of a combination of differences in reproductive success, en masse larval dispersion and local larval retention. This study defines P. marmoratus as an example of marine spawner whose genetic pool is not homogenous at population level, but rather split in a chaotic mosaic of slightly differentiated genetic patches derived from complex and dynamic ecological processes.

First report of Sus strozzii (Suidae, Mammalia) from the Early Pleistocene of Hungary (Dunaalmás) and species distinction based on deciduous teeth

Herein we describe a fragment of a mandible with a deciduous fourth premolar (dp4) from the Early Pleistocene locality of Dunaalmás, representing the first confirmed report of Sus strozzii from Hungary. The comparison of dp4 measurements supports a statistically significant distinction between S. strozzii and Sus scrofa. The two species overlap in time during the late Early Pleistocene of Europe (Epivillafranchian), but suid remains of this time-span are seldom classified at a species level. The correct taxonomic identification of the Epivillafranchian suids, which are often associated with evidences of hominin presence, is of great palaeoenvironmental value because S. scrofa and S. strozzii possess different ecological requirements.

Conserved sex chromosomes and karyotype evolution in monitor lizards (Varanidae)

Despite their long history with the basal split dating back to the Eocene, all species of monitor lizards (family Varanidae) studied so far share the same chromosome number of 2n = 40. However, there are differences in the morphology of the macrochromosome pairs 5-8. Further, sex determination, which revealed ZZ/ZW sex microchromosomes, was studied only in a few varanid species and only with techniques that did not test their homology. The aim of this study was to (i) test if cryptic interchromosomal rearrangements of larger chromosomal blocks occurred during the karyotype evolution of this group, (ii) contribute to the reconstruction of the varanid ancestral karyotype, and (iii) test homology of sex chromosomes among varanids. We investigated these issues by hybridizing flow sorted chromosome paints from Varanus komodoensis to metaphases of nine species of monitor lizards. The results show that differences in the morphology of the chromosome pairs 5-8 can be attributed to intrachromosomal rearrangements, which led to transitions between acrocentric and metacentric chromosomes in both directions. We also documented the first case of spontaneous triploidy among varanids in Varanus albigularis. The triploid individual was fully grown, which demonstrates that polyploidization is compatible with life in this lineage. We found that the W chromosome differs between species in size and heterochromatin content. The varanid Z chromosome is clearly conserved in all the analyzed species. Varanids, in addition to iguanas, caenophidian snakes, and lacertid lizards, are another squamate group with highly conserved sex chromosomes over a long evolutionary time.

Genome of the Komodo dragon reveals adaptations in the cardiovascular and chemosensory systems of monitor lizards

Monitor lizards are unique among ectothermic reptiles in that they have high aerobic capacity and distinctive cardiovascular physiology resembling that of endothermic mammals. Here, we sequence the genome of the Komodo dragon Varanus komodoensis, the largest extant monitor lizard, and generate a high-resolution de novo chromosome-assigned genome assembly for V. komodoensis using a hybrid approach of long-range sequencing and single-molecule optical mapping. Comparing the genome of V. komodoensis with those of related species, we find evidence of positive selection in pathways related to energy metabolism, cardiovascular homoeostasis, and haemostasis. We also show species-specific expansions of a chemoreceptor gene family related to pheromone and kairomone sensing in V. komodoensis and other lizard lineages. Together, these evolutionary signatures of adaptation reveal the genetic underpinnings of the unique Komodo dragon sensory and cardiovascular systems, and suggest that selective pressure altered haemostasis genes to help Komodo dragons evade the anticoagulant effects of their own saliva. The Komodo dragon genome is an important resource for understanding the biology of monitor lizards and reptiles worldwide.

Isolating Chromosomes of the Komodo Dragon: New Tools for Comparative Mapping and Sequence Assembly

We developed new tools to build a high-quality chromosomal map of the Komodo dragon (Varanus komodoensis) available for cross-species phylogenomic analyses. First, we isolated chromosomes by flow sorting and determined the chromosome content of each flow karyotype peak by FISH. We then isolated additional Komodo dragon chromosomes by microdissection and amplified chromosome-specific DNA pools. The chromosome-specific DNA pools can be sequenced, assembled, and mapped by next-generation sequencing technology. The chromosome-specific paint probes can be used to investigate karyotype evolution through cross-species chromosome painting. Overall, the set of chromosome-specific DNA pools of V. komodoensis provides new tools for detailed phylogenomic analyses of Varanidae and squamates in general.

Insights into Emydid Turtle Cytogenetics: The European Pond Turtle as a Model Species

Our knowledge of Testudines evolution is limited by the lack of modern cytogenetic data. Compared to other reptiles, there is little information even on chromosome banding, let alone molecular cytogenetic data. Here, we provide detailed information on the karyotype of the European pond turtle Emys orbicularis, a model Emydidae, employing both chromosome banding and molecular cytogenetics. We provide a high-resolution G-banded karyotype and a map of rDNA genes and telomeric sequences using fluorescence in situ hybridization. We test hypotheses of sex-determining mechanisms in Emys by comparative genomic hybridization to determine if Emys has a cryptic sex-specific region. Our results provide valuable data to guide future efforts on genome sequencing and anchoring in Emydidae and for understanding karyotype evolution in Testudines.

Involvement of the Central Nervous System in Non-Hodgkin's Lymphoma

Fifteen of 146 (10 %) adult patients with non-Hodgkin's lymphoma showed clinical and pathologic evidence of involvement of the central nervous system (CNS); in 6 patients, the CNS lymphoma was present at the onset of disease, in 3 of them it was the only sign detected. In the remaining 9 cases, CNS involvement appeared during the course of systemic disease. In all cases symptoms related to infiltration of the CNS were associated with advanced disease (stage IV); bone marrow or bone involvement was found in 9 patients (60 %). The histologic subtypes were mostly of high-grade malignancy according to the Kiel classification: immunoblastic (3), centroblastic (3), Burkitt type (2), lymphoblastic (1), LP immunocytoma in polymorphic variant (3), unclassifiable (3). The prominent signs and symptoms of CNS lymphoma are listed: the cranial nerve palsies are the most common finding. The principal means of detecting CNS involvement are discussed: cerebrospinal fluid cytology, brain scan and CAT scan were the most useful diagnostic procedures. The reported data allow identification of patients at high risk of CNS lymphoma: this includes histologies of high-grade malignancy, advanced stage of disease, and bone marrow or bone infiltration. Therefore, either intensive systemic chemotherapy or CNS prophylaxis are recommended for patients with high risk of CNS disease.

Effect of ammonia on the gene expression levels of the freshwater cyclopoid Eucyclops serrulatus

Ammonia pollution is a critical issue in Europe, since more than half of the European freshwater bodies actually fail to meet EU quality standards for this chemical. In this study, the response of stress-related genes to a sublethal ammonia concentration has been investigated in the adults of the freshwater cyclopoid Eucyclops serrulatus. Two short-term exposures (12h and 24h) at 12mg/L NH₄⁺ have been tested. Results indicate that 12mg/L NH₄⁺ causes a significant increase in the expression of some proteins, namely CAT, HSP90 and HSP40, suggesting an activation of the protecting antioxidant system after both 12h and 24h.

Genomic resources notes accepted 1 October 2014-30 November 2014

This article documents the public availability of (i) RAD sequencing data and validated SNPs for the American mink Neovison vison and (ii) Transcriptome resources for two nonmodel freshwater crustacean species, the copepod Eucyclops serrulatus and the amphipod Echinogammarus veneris.

Sensitivity of hypogean and epigean freshwater copepods to agricultural pollutants

Widespread pollution from agriculture is one of the major causes of the poor freshwater quality currently observed across Europe. Several studies have addressed the direct impact of agricultural pollutants on freshwater biota by means of laboratory bioassays; however, as far as copepod crustaceans are concerned, the ecotoxicological research is scarce for freshwater species and almost nonexistent for the hypogean ones. In this study, we conducted a comparative analysis of the available literature data on the sensitivity of freshwater copepods to agricultural pollutants. We also assessed the acute and chronic sensitivity of a hypogean and an epigean species, both belonging to the Crustacea Copepoda Cyclopoida Cyclopidae, to two N-fertilizers (urea and ammonium nitrate) and two herbicides (ARIANE(TM) II from Dow AgroSciences LLC, and Imazamox), widely used for cereal agriculture in Europe. According to the literature review, freshwater copepods are sensitive to a range of pesticides and N-fertilizers. Ecotoxicological studies on hypogean species of copepods account only one study. There are no standardized protocols available for acute and chronic toxicity tests for freshwater copepods, making comparisons about sensitivity difficult. From our experiments, ionized ammonia proved to be more toxic than the herbicide Imazamox, in both short and chronic bioassays. Urea was the less toxic chemical for both species. The hypogean species was more sensitive than the epigean one to all chemicals. For both species and for all tested chemicals, acute lethality and chronic lethality were induced at concentrations higher than the law limits of good water body quality in Europe, except for ionized ammonia, which provoked the chronic lethality of the hypogean species at a lower concentration. The hazardous concentration (HC) of un-ionized ammonia for 5 % of freshwater copepods, obtained by a species sensitivity distribution, was 92 μg l(-1), significantly lower than the HC computed for traditional test species from freshwater environments.

Oncocytic papillary renal cell carcinoma: potential pitfall in small enucleation

OBJECTIVE

We describe an emerging entity, recently recognized as a pitfall in the diagnostic practice among eosinophilic renal cell tumours.

METHODS

A 60-year-old male underwent enucleation of a 1.2 cm nodule. Immunohistochemistry and FISH analysis were performed.

RESULTS

Histology revealed a neoplasm composed of large cells with eosinophilic cytoplasm, Fuhrman grade 3, arranged in papillae. At the immunohistochemical level, cells showed positivity for AMACR and CD10. Fluorescence in situ hybridization (FISH) demonstrated gains of chromosomes 7 and 17 and loss of Y. A diagnosis of oncocytic papillary renal cell carcinoma was made.

CONCLUSIONS

The distinction between renal oncocytoma and oncocytic papillary renal cell carcinoma is of substantial importance because of their different behaviour and prognosis, since the latter has malignant potential. Although the available evidence supporting tumour enucleation as the surgical treatment for renal cortical tumours < or = 4 cm, due to aforementioned clinicopathological features such tumours need to be evaluated using appropriate immunophenotypical and cytogenetic analyses.

[Perianal Paget's disease: five cases report]

AIM

Extramammary Paget's disease is a rare neoplastic condition, often associated with a synchronous or metachronous underlying skin or visceral malignancies. The aim of this study was to evaluate retrospectively the results we got in 5 cases of perianal Paget's disease and to revise what literature have reported about this issue.

PATIENTS AND METHODS

Five patients with perianal EMPD were consecutively treated in our Division between March 1996 and December 2006. In 3 cases the disease was limited to the epidermidis, in one case with multiple recurrences there was dermal infiltration, and one patient had a low rectal adenocarcinoma with pagetoid phenomenon. The surgical treatment we performed in all patients was a wide perianal excision, followed by reconstruction with cutaneous grafts; the resection of rectal adenocarcinoma was carried out using the transanal approach. In two cases we performed a temporary stoma with the sigmoid colon to help the wound healing.

RESULTS

We didn't record any complication neither postoperative nor at long time. Two patients developed a local recurrence, but none of our patients showed distant metastases. Four patients are alive and free from disease and one, who developed a multiple local recurrences, died for heart failure.

DISCUSSION

The studies available in literature clearly distinguish between a primary EMPD (intraepidermal/intradermal) and secondary disease which is associated with anorectal adenocarcinomas and is thought to be a pagetoid phenomenon, while few informations can derive from those cases in which the disease is associated with an underlying cutaneous adnexal carcinoma. Disease tend to relapse even after a radical surgery and can have metastatic spread, also in intraepidermal form.

CONCLUSIONS

Perianal EMPD is a complex disease, difficult to recognize and the association with synchronous or metachronous malignancies imposes long term clinical and instrumental follow up.

Independent prognostic value of fascin immunoreactivity in stage I nonsmall cell lung cancer

Fascin-1, the most expressed form of fascin in vertebrate tissues, is an actin-bundling protein that induces cell membrane protrusions and increases motility of normal and transformed epithelial cells. Very few data are available on the role of this protein in nonsmall cell lung cancer (NSCLC). Two hundred and twenty patients with stage I NSCLC and long-term follow-up were evaluated immunocytochemically for fascin expression. Overall, variable fascin immunoreactivity was detected in 98% of 116 squamous cell carcinomas, in 78% of 96 adenocarcinomas, in 83% of six large cell carcinomas, and in the two adenosquamous carcinomas under study. Neoplastic emboli were commonly decorated by the antifascin antibody (P<0.001), also when the surrounding invasive carcinoma was unreactive. Fascin immunoreactivity correlated with high tumour grade (P=0.017) and, in adenocarcinomas, with high Ki-67 labelling index (P=0.021). Adenocarcinomas with a prevalent bronchiolo-alveolar in situ component were less commonly immunoreactive for fascin than invasive tumours (P=0.005). Contralateral thoracic or distant metastases were associated significantly with diffuse (>60% immunoreactive tumour cells) fascin expression in adenocarcinomas (P=0.043), and marginally with strong fascin immunostaining in squamous cell carcinomas (P=0.13). No associations were noted with any other clinicopathological variables tested. Patients with tumours showing diffuse (>60% immunoreactive neoplastic cells) and/or strong immunoreactivity for fascin had a shorter survival (P=0.006 for adenocarcinomas and P=0.026 for squamous cell carcinomas), even after multivariate analysis (P=0.014 and 0.050, respectively). The current study documents for the first time that fascin is upregulated in invasive and more aggressive NSCLC, being an independent prognostic predictor of unfavourable clinical course of the disease. Targetting the fascin pathway could be a novel therapeutic strategy of NSCLC.

[Peutz-Jeghers syndrome: case report and update on diagnosis and treatment]

Peutz-Jeghers syndrome is a rare autosomal dominantly inherited condition with an incidence of 1/120.000 liveborns, characterized by the presence of hamartomatous gastrointestinal polyps and mucocutaneous pigmentation. This syndrome predisposes to various clinical problems such as intussusception and cancer development in different loci (gastrointestinal tract, breast and ovary). For this reason, PJS patients should undergo a surveillance protocol of the genital and gastrointestinal apparatus. Therefore, the early diagnosis of PJS in at-risk family members is very important in preventing cancer development. Germline mutations within the LKB1 or Serine Threonine Kinase (STK11) gene, located on chromosome 19p13.3, are responsible for most cases of PJS so far studied. The existence of a second locus is suspected on chromosome 19q13.4 in a minority of families. The LKB1 gene, recently cloned, encodes the Serine Threonine Kinase LKB1 and is ubiquitously expressed. The identification of the disease-causing mutation in each family makes it possible to perform a presymptomatic diagnosis; therefore, only the mutation carriers will undergo the clinical surveillance program. In this paper, the case of a PJS patient who has been surgically treated is presented. The DNA screening of the LKB1 gene in this patient has led to the identification of the causing mutation. A critical review of the literature and is also presented as well as the proposal to establish an Italian Registry of PJS.

[Current problems of the surgical treatment of rectal cancer: analysis of the literature and personal experience]

The surgical procedure is a crucial factor in preventing local recurrence in rectal cancer, and total mesorectal excision (TME) particularly is widely accepted as being associated with a decreased local recurrence rate. In this study, concerning 187 patients with rectal cancer, we compare conventional surgery, performed in 140 patients from 1979 to 1993, with a standardised TME procedure in 47 patients over the period from 1994 to 1998. The first group not treated by TME were operated on for 56 (40%) tumours of the upper rectum and 84 (60%) of the lower rectum; 35 (25%) were Dukes' A, 77 Dukes' B and 28 (20%) Dukes' C. 42 abdominoperineal amputations (30%) and 98 anterior resections (70%) were performed. The second group in which TME was performed comprised 17 (36%) tumours of the upper rectum and 30 (64%) of the lower rectum, 8 (17%) in stage I AJCC (Dukes' A), 16 (34%) in II (B) and 23 (49%) in III (C). 9 abdominoperineal amputations (19%) and 38 anterior resections (81%) were performed, 8 (21%) with an ultra-low anastomosis. In the first group of patients we observed 28 local recurrences (20%) and a 5-year disease-free survival in 50% of cases. In the second group we achieved a decreased rate of local recurrence (10.6%) which is about half that observed after conventional surgery, but there was no significant difference in survival. These data confirm the effectiveness of TME in reducing local recurrence rate, according to the literature; in future this procedure can get to reconsider the role of adjuvant therapy in the management of rectal cancer.

Immunoreactivity for thyroid transcription factor-1 in stage I non-small cell carcinomas of the lung

Thyroid transcription factor-1 (TTF-1) is a nuclear protein regulating the transcriptional activity of lung-specific genes in the normal and neoplastic bronchioloalveolar cells. It has been implicated in the normal growth and development of the lung, and the disruption of the TTF-1 locus leads to neonatal death with pulmonary hypoplasia. We evaluated retrospectively the prevalence and clinical significance of TTF-1 immunoreactivity in 222 patients with stage I non-small cell lung carcinoma (NSCLC) with a follow-up time of at least 5 years, and we investigated its relationship with other markers of tumor growth, namely cell proliferation and angiogenesis. TTF-1 immunoreactivity was documented by using the commercially available monoclonal antibody 8G7G3/1 in 72% of 97 adenocarcinomas, 5% of 119 squamous cell carcinomas, and in the glandular component of two adenosquamous carcinomas. Four large cell carcinomas were completely unreactive. In adenocarcinomas, but not squamous cell carcinomas, TTF-1 immunoreactivity correlated significantly with microvessel density (p = 0.04) and inversely with the tumor proliferation fraction assessed by Ki-67 immunostaining (p = 0.03). Also, TTF-1-immunoreactive adenocarcinomas showed a trend for a size less than 3 cm (p = 0.08). TTF-1 expression was not related to specific growth patterns, tumor grade, or tumor cell typing. TTF-1 immunoreactivity did not significantly affect patient survival, although patients with more than 75% immunoreactive neoplastic cells showed a trend for longer overall and disease-free survival. Our findings suggest that TTF-1 could be involved in the development of small pulmonary adenocarcinomas, but it has not prognostic implications in patients with stage I NSCLC.

Surgical treatment of pancreatic metastases from renal cell carcinomas

Pancreatic metastases from a renal cell carcinoma are rare and may occur long after manifestation of the primary disease. Resection of the metastases should be regarded as the best treatment. In our center, owing to the slow evolution of these secondaries, we perform resections capable of limiting the destruction of the pancreatic parenchyma as far as possible. The use of 'atypical' resections of the pancreas is characterized by a higher incidence of postoperative complications, particularly fistulas. Despite this, we believe that adjusted resection is to be advocated because of the possibility of additional remote secondaries, the shorter duration of surgery, the preservation of the glandular parenchyma and intact adjacent organs, such as duodenum, stomach, and spleen, and the fact that there have been no reports on local recurrences.

A phase II study of biochemotherapy for the treatment of metastatic malignant melanoma

The use of interleukin-2 (IL-2) and interferon-alpha (IFNalpha) in combination with chemotherapy for the treatment of advanced malignant melanoma has generated considerable interest. In particular, the relatively high number of durable complete responses has suggested this may be a significant advance in the treatment of malignant melanoma. We report our experience at the University of Colorado in 43 patients, including many with poor prognostic factors. Patients received cisplatin 20 mg/m2 on days 1-4, vinblastine 1.6 mg/m2 on days 1-4, dacarbazine 800 mg/m2 on day 1, IL-2 9 x 10(6) IU/m2 per day intravenously over 24h on days 1-4 and IFNalpha 5 x 10(6) IU/m2 per day subcutaneously on days 1-5 every 3 weeks. The median follow-up for all patients was 34 months. Responses were seen in 20 patients (47%, 95% confidence interval 31-62%) and comprised five complete responses (CRs) (12%) and 15 partial responses (PRs) (35%). Two patients achieving a CR remain disease free at 45 and 47 months follow-up. In addition three patients who obtained a surgical CR and another with only minor residual changes on computed tomography scan have not progressed at 27, 30, 40 and 27 months, respectively. Toxicity was manageable, but all patients had at least one grade 3 or 4 toxicity, predominantly hypotension and neutropenia. There were no treatment-related deaths. In conclusion, the response rate and duration is within the range previously reported for biochemotherapy. The results of ongoing randomized studies are awaited to better define the value of biochemotherapy in the treatment of advanced melanoma.

Immunocytochemical assessment of bone marrow aspirates for monitoring response to chemotherapy in small-cell lung cancer patients

Recent reports have suggested that tumour cell immunodetection in bone marrow of small-cell lung cancer patients is by far more frequent than found cytohistologically and may have clinical relevance. This study evaluates primarily the efficacy of chemotherapy as method of in vivo purging, but also the relationship of marrow involvement with survival. A total of 112 bone marrow aspirates from 30 chemo-naïve patients were stained twice using anti-NCAM antibodies, first at diagnosis and then after chemotherapy (24 patients) or at disease progression (six patients). Marrow contamination was associated with lower survival (P = 0.002), and was also detected in 7/17 patients conventionally staged as having limited disease. At multivariate analysis, marrow involvement was an independent factor of unfavourable prognosis (P = 0.033). The amount of tumour contamination, before and after chemotherapy, remained unchanged also in responders and even in the subset of patients with apparent limited disease. Following chemotherapy, bone marrow became tumour negative only in 25% of initially positive responders and in none of non-responders. Our results indicate that (i) chemotherapy is not effective in purging bone marrow even in chemo-responsive patients and (ii) a subset of patients with limited disease and negative bone marrow aspirates might have a more favourable prognosis.

Fibro-osseous lesions of the central nervous system: report of four cases and literature review

Fibro-osseous lesions, also reported as calcifying pseudoneoplasms of the neural axis, are uncommon lesions of the CNS. We report four additional cases: two extraaxial and two intraaxial, in patients ages 33, 47, 49, and 59 years at presentation. Fibro-osseous lesions involving the CNS demonstrate variable proportions of fibrous stroma, bone, palisading spindle to epithelioid to multinucleated cells in association with a highly distinctive, perhaps pathognomonic, chondromyxoid-like matrix often distributed in a nodular pattern. This histopathologically distinctive lesion can be seen in many regions of the neuraxis, often with a dural association, and most commonly along the vertebral column. It appears to be a slow-growing lesion and, with wide excision, the prognosis is excellent. The etiology remains unclear, but the preponderance of data favors a reactive rather than neoplastic process. If this putative pseudotumor is not recognized histopathologically, a neoplastic or infectious differential might result in inappropriate investigations and potentially harmful therapies.

Effects of different immunolabeling techniques on the detection of small-cell lung cancer cells in bone marrow

Recent reports have suggested that the immunodetection of tumor cells in bone marrow of small-cell lung cancer (SCLC) patients is by far more effective than traditional cytohistological methods and that this may be clinically relevant. This study aimed to evaluate whether the level of detection of tumor cells in bone marrow is affected by different immunostaining methods. Using two anti-NCAM monoclonal antibodies (MAbs), we compared four different "sandwich" methods on cytospin preparations of the N592 human SCLC cell line and of bone marrow aspirates from 37 SCLC patients. Our data indicate that the combination of the alkaline phosphatase-anti-alkaline phosphatase and streptavidin-biotin-alkaline phosphatase complex methods provides the best results in terms of sensitivity and specificity, and of intensity of immunoreaction and absence of staining background. Moreover, bone marrow micrometastases detected by this method were prognostically relevant and identified, among patients with apparently limited disease according to conventional staging procedures, a subgroup with shorter survival. We suggest that the choice of a sensitive immunostaining technique may significantly increase the detection rate of SCLC cells in bone marrow, mirroring the biological aggressiveness of the disease.

Solid and cystic papillary neoplasm of the pancreas: a clinico-cytopathologic and immunocytochemical study of five new cases diagnosed by fine-needle aspiration cytology and a review of the literature

We report here on five new cases of solid and cystic papillary neoplasm (SCPN) of the pancreas diagnosed by fine-needle aspiration cytology (FNAC). All cytologic samples were obtained by ultrasonography, and the smears were conventionally fixed and stained. Special histochemical and immunocytochemical stains were also performed in some samples. Cytology revealed in all but one case numerous pseudopapillary structures composed of fibrovascular stalks lined with one or more layers of bland-appearing, uniform tumor cells. The tumor cells had round-to-oval euchromatic nuclei with frequently folded smooth contours and one or two small nucleoli. Their cytoplasm often contained eosinophilic, PAS-positive, and diastase-resistant inclusions. Foamy cells, psammoma bodies, blood, and cellular debris were found in the background. The criteria for the differential diagnosis versus other pancreatic lesions are discussed in some detail, as is the role of immunocytochemistry (ICC). In the literature, only 28 cases of cytologically investigated SCPN have been reported to the best of our knowledge. The most helpful criteria for the conclusive identification of SCPN by FNAC include the pseudopapillary arrangement with bland-appearing tumor cells, and, especially, the finding of acidophilic, PAS-positive, and diastase-resistant cytoplasmic granules.

PSA-negative tumours of the prostate

The immunoperoxidase staining of normal and hyperplastic prostatic epithelium for Prostate Specific Antigen (PSA) is, with few exceptions, uniform and strong. In contrast to the benign tissue, most reports of prostatic adenocarcinoma demonstrated an apparent correlation between staining-variability and increasing tumour grades. Decreased PAP staining may be related to incorrect manipulation of prostatic tissue. Finally there are many tumours and pseudotumours of the prostate in which the PSA stain is regularly negative. In the differential diagnosis of prostate tumour, both PSA and PAP (Prostatic Acid Phosphatase) stains should be performed. It is mandatory that the stains be interpreted in the appropriate histologic and clinicopathologic setting with due consideration of positive and negative staining.

Expression of proliferating cell nuclear antigen, Ki-67 antigen, estrogen receptor protein, and tumor suppressor p53 gene in cytologic samples of breast cancer: an immunochemical study with clinical, pathobiological, and histologic correlations

Sixty-six unselected breast cancers were analyzed in cytologic smears and histologic sections for the expression of Ki-67, proliferating cell nuclear antigen (PCNA), estrogen receptor protein (ERP), and p53 protein using a standard immunochemical method. The results, expressed as both positive cases and labelling index (LI), were compared with clinical and pathobiological variables. Ki-67 and PCNA immunostaining was seen in all cases, whereas ERP was detectable in 46/63 cases and p53 protein in 20/66 cases. The expression of these markers was generally lower in cytology than in histology, though the differences were not statistically significant. PCNA-LI and Ki-67-LI were closely correlated (P < 0.001), the mean PCNA:Ki-67 ratio being 0.92 +/- 0.57. Occasional discrepancies, however, were found. PCNA and Ki-67 expression was associated with an increase in histologic grade and a decrease in ERP content of tumors, whereas p53 was statistically associated with no clinical or pathobiological variables. The data suggest that proliferative activity and oncogene overexpression may be reliably evaluated in breast cancer by FNA cytology, though PCNA is not a suitable indicator for cell proliferation. The results do not resolve the issue as to whether immunostaining for p53 protein constitutes a dedifferentiation product of the tumor, or is a fundamental aspect of the malignant progression. Survival studies in a larger series of tumors are thus needed to elucidate this point.

Immunocytochemical detection of cell proliferation-related antigens in cytologic smears of human malignant neoplasms using PC10, reactive with proliferating cell nuclear antigen, and Ki-67. A comparative study

Cytospins of the MCF-7 cell line and 93 consecutive smears of human malignant neoplasms were immunochemically evaluated for the expression of proliferating cell nuclear antigen (PCNA) and Ki-67-related antigen. Results expressed as the labeling index (LI) were compared with histologic sections. The PCNA LI and Ki-67 LI were lower in cytologic smears than in histologic sections, though the differences were not statistically significant. A positive linear relationship was found between these markers in both cytologic and histologic samples. The PCNA LI was generally lower than the Ki-67 LI, but in seven malignant neoplasms, PCNA LI was greater than the corresponding values of the KI-67 LI. We conclude that cell proliferation can be reliably evaluated on cytologic preparations; PCNA may behave as a Ki-67-like reagent in some tumors, and PCNA may sometimes overestimate the cell growth fraction assessed by Ki-67 immunoreactivity.

Breast solitary schwannoma: fine-needle aspiration biopsy and immunocytochemical analysis

A case of intramammary solitary schwannoma (SS) (benign neurilemoma) diagnosed by fine-needle aspiration biopsy (FNAB) and supported by immunocytochemical study is reported. The tumor arose in the right breast of an 18-yr-old woman and was clinically and radiologically considered a fibroadenoma. The smears obtained by FNAB of the lump showed clusters of spindle-shaped cells and suggested a benign mesenchymal neoplasm. The presence of some structures reminiscent of Verocay bodies and the immunocytochemical reactivity for S-100 protein antiserum demonstrated the schwannian nature of the tumor and suggested the diagnosis of SS. The final histologic examination confirmed the cytologic diagnosis.

Methodological aspects of the immunostaining of proliferating cell nuclear antigen (PCNA) in cytospin preparations of MCF-7 cell line

Cytospins of a human breast cancer cell line (MCF-7) were studied for the expression of PCNA, a cell cycle-related protein, using a variety of fixation and immunostaining procedures. The best fixative for PCNA was found to be buffered formaldehyde solution at 4 degrees C followed by methanol at 20 degrees C, whereas alcoholic fixatives decreased greatly the PCNA immunoreactivity. Air-drying procedures of cytospins prior to and after fixation greatly undermined the PCNA immunostaining. A modified immunoperoxidase method provided a stronger staining of the PCNA-reactive cells than the alkaline phosphatase anti-alkaline phosphatase (APAAP) technique. PCNA immunoreactivity could be maintained up to 2 mo, putting slides in methanol at -20 degrees C. In conclusion, our report indicates that PCNA is a labile antigen, which may critically be affected by temperature and air-drying procedures.

Expression of progesterone receptors in solid-cystic tumour of the pancreas: a clinicopathological and immunohistochemical study of ten cases

A role for sex hormones in the pathogenesis of solid-cystic tumour (SCT) of the pancreas is suggested by its predilection for young fertile women. Controversial data have been provided for the presence of progesterone receptors (PR) and/or oestrogen receptors (ER) in SCT. We report the immunohistochemical detection of PR in ten cases of SCT. Eight were from young women. The remaining two were from a post-menopausal woman and a young boy. All cases showed PR immunoreactivity in the large majority of neoplastic cells, whereas none exhibited ER positivity. In one tumour two types of cell populations were noted, the more anaplastic invasive-type being PR negative, whereas the more typical was PR positive. PR immunoreactivity in the absence of ER may simply reflect a lower sensitivity of ER antibody failing to reveal the biochemically detectable ER, or that the PR in cells of SCT are constitutively synthesized in an oestrogen-independent way, as in T47D breast carcinoma cell line, meningioma cells and some gastric cancer cells. Our findings support the hypothesis of a possible pathogenetic role of progesterone in SCT, independent of the patient's sex and age.