Supra-organismal regulation of strigolactone exudation and plant development in response to rhizospheric cues in rice.

Plants have evolved elaborate mechanisms to detect neighboring plants, which typically involve the perception of "cues" inadvertently produced by the neighbor.1 Strigolactones are hormonal signaling molecules2,3 that are also exuded into the rhizosphere by most flowering plant species to promote arbuscular mycorrhizal symbioses.4 Since flowering plants have an endogenous perception system for strigolactones,5 strigolactones are obvious candidates to act as a cue for neighbor presence, but have not been shown to act as such. To test this hypothesis in rice plants, we quantified two major strigolactones of rice plants, orobanchol and 4-deoxyorobanchol, in root exudates by using LC-MS/MS (MRM) and examined feedback regulation of strigolactone biosynthesis and changes in shoot branching phenotypes in rice plants grown at different densities in hydroponics and soil culture. We show that the presence of neighboring plants, or greater root volume, results in rapidly induced changes in strigolactone biosynthesis, sensitivity, and exudation and the subsequent longer-term changes in shoot architecture. These changes require intact strigolactone biosynthesis in neighboring plants and intact strigolactone signaling in focal plants. These results suggest that strigolactone biosynthesis and exudation in rice plants are driven by supra-organismal environmental strigolactone levels. Strigolactones thus act as a cue for neighbor presence in rice plants, but also seem to act as a more general root density-sensing mechanism in flowering plants that integrates soil volume and neighbor density and allows plants to adapt to the limitations of the rhizosphere.

Strigolactones Modulate Salicylic Acid-Mediated Disease Resistance in Arabidopsis thaliana.

Strigolactones are low-molecular-weight phytohormones that play several roles in plants, such as regulation of shoot branching and interactions with arbuscular mycorrhizal fungi and parasitic weeds. Recently, strigolactones have been shown to be involved in plant responses to abiotic and biotic stress conditions. Herein, we analyzed the effects of strigolactones on systemic acquired resistance induced through salicylic acid-mediated signaling. We observed that the systemic acquired resistance inducer enhanced disease resistance in strigolactone-signaling and biosynthesis-deficient mutants. However, the amount of endogenous salicylic acid and the expression levels of salicylic acid-responsive genes were lower in strigolactone signaling-deficient max2 mutants than in wildtype plants. In both the wildtype and strigolactone biosynthesis-deficient mutants, the strigolactone analog GR24 enhanced disease resistance, whereas treatment with a strigolactone biosynthesis inhibitor suppressed disease resistance in the wildtype. Before inoculation of wildtype plants with pathogenic bacteria, treatment with GR24 did not induce defense-related genes; however, salicylic acid-responsive defense genes were rapidly induced after pathogenic infection. These findings suggest that strigolactones have a priming effect on Arabidopsis thaliana by inducing salicylic acid-mediated disease resistance.

Germination Stimulant Activity of Isothiocyanates on Phelipanche spp.

The root parasitic weed broomrapes, Phelipanche spp., cause severe damage to agriculture all over the world. They have a special host-dependent lifecycle and their seeds can germinate only when they receive chemical signals released from host roots. Our previous study demonstrated that 2-phenylethyl isothiocyanate is an active germination stimulant for P. ramosa in root exudates of oilseed rape. In the present study, 21 commercially available ITCs were examined for P. ramosa seed germination stimulation, and some important structural features of ITCs for exhibiting P. ramosa seed germination stimulation have been uncovered. Structural optimization of ITC for germination stimulation resulted in ITCs that are highly active to P. ramosa. Interestingly, these ITCs induced germination of P. aegyptiaca but not Orobanche minor or Striga hermonthica. P. aegyptiaca seeds collected from mature plants parasitizing different hosts responded to these ITCs with different levels of sensitivity. ITCs have the potential to be used as inducers of suicidal germination of Phelipanche seeds.

Response of tomatoes primed by mycorrhizal colonization to virulent and avirulent bacterial pathogens.

Most plants interact with arbuscular mycorrhizal fungi, which enhance disease resistance in the host plant. Because the effects of resistance against bacterial pathogens are poorly understood, we investigated the effects of mycorrhizal colonization on virulent and avirulent pathogens using phytopathological and molecular biology techniques. Tomato plants colonized by Gigaspora margarita acquired resistance not only against the fungal pathogen, Botrytis cinerea, but also against a virulent bacterial pathogen, Pseudomonas syringae pv. tomato DC3000 (Pst). In G. margarita-colonized tomato, salicylic acid (SA)- and jasmonic acid (JA)-related defense genes were expressed more rapidly and strongly compared to those in the control plants when challenged by Pst, indicating that the plant immunity system was primed by mycorrhizal colonization. Gene expression analysis indicated that primed tomato plants responded to the avirulent pathogen, Pseudomonas syringae pv. oryzae, more rapidly and strongly compared to the control plant, where the effect on the JA-mediated signals was stronger than in the case with Pst. We found that the resistance induced by mycorrhizal colonization was effective against both fungal and bacterial pathogens including virulent and avirulent pathogens. Moreover, the activation of both SA- and JA-mediated signaling pathways can be enhanced in the primed plant by mycorrhizal colonization.

Characterization of a Chickpea Mutant Resistant to Phelipanche aegyptiaca Pers. and Orobanche crenata Forsk.

Chickpea (Cicer arietinum L.) is a major pulse crop in Israel grown on about 3000 ha spread, from the Upper Galilee in the north to the North-Negev desert in the south. In the last few years, there has been a gradual increase in broomrape infestation in chickpea fields in all regions of Israel. Resistant chickpea cultivars would be simple and effective solution to control broomrape. Thus, to develop resistant cultivars we screened an ethyl methanesulfonate (EMS) mutant population of F01 variety (Kabuli type) for broomrape resistance. One of the mutant lines (CCD7M14) was found to be highly resistant to both Phelipanche aegyptiaca and Orobanche crenata. The resistance mechanism is based on the inability of the mutant to produce strigolactones (SLs)-stimulants of broomrape seed germination. LC/MS/MS analysis revealed the SLs orobanchol, orobanchyl acetate, and didehydroorobanchol in root exudates of the wild type, but no SLs could be detected in the root exudates of CCD7M14. Sequence analyses revealed a point mutation (G-to-A transition at nucleotide position 210) in the Carotenoid Cleavage Dioxygenase 7 (CCD7) gene that is responsible for the production of key enzymes in the biosynthesis of SLs. This nonsense mutation resulted in a CCD7 stop codon at position 70 of the protein. The influences of the CCD7M14 mutation on chickpea phenotype and chlorophyll, carotenoid, and anthocyanin content were characterized.

Strigolactone biosynthesis catalyzed by cytochrome P450 and sulfotransferase in sorghum.

Root parasitic plants such as Striga, Orobanche, and Phelipanche spp. cause serious damage to crop production world-wide. Deletion of the Low Germination Stimulant 1 (LGS1) gene gives a Striga-resistance trait in sorghum (Sorghum bicolor). The LGS1 gene encodes a sulfotransferase-like protein, but its function has not been elucidated. Since the profile of strigolactones (SLs) that induce seed germination in root parasitic plants is altered in the lgs1 mutant, LGS1 is thought to be an SL biosynthetic enzyme. In order to clarify the enzymatic function of LGS1, we looked for candidate SL substrates that accumulate in the lgs1 mutants and performed in vivo and in vitro metabolism experiments. We found the SL precursor 18-hydroxycarlactonoic acid (18-OH-CLA) is a substrate for LGS1. CYP711A cytochrome P450 enzymes (SbMAX1 proteins) in sorghum produce 18-OH-CLA. When LGS1 and SbMAX1 coding sequences were co-expressed in Nicotiana benthamiana with the upstream SL biosynthesis genes from sorghum, the canonical SLs 5-deoxystrigol and 4-deoxyorobanchol were produced. This finding showed that LGS1 in sorghum uses a sulfo group to catalyze leaving of a hydroxyl group and cyclization of 18-OH-CLA. A similar SL biosynthetic pathway has not been found in other plant species.

Evaluation and Quantification of Natural Strigolactones from Root Exudates.

Strigolactones (SLs) in the root exudates can be detected by germination assays with root parasitic weed seeds, but precise and accurate evaluation and quantification are possible only by chemical analysis with the liquid chromatography-tandem mass spectrometry (LC-MS/MS). Here we describe methods for root exudate collection, sample preparation, and LC-MS/MS analysis of SLs.

Retrospective outcome in women aged 45 years and older undergoing natural cycle IVF treatment.

RESEARCH QUESTION: Is natural cycle IVF treatment beneficial to middle-aged women with poor ovarian response? DESIGN: Retrospective investigation of outcomes in women aged 45 years and older, who underwent natural cycle IVF treatment between 2009 and 2018 in a single assisted reproduction clinic with the aim of reporting several successful outcomes. RESULTS: In total, 2408 IVF retrievals in women aged 45 years and older were included in this study. Mean serum FSH level on day 3 was 21.4 ± 12.5 (range: 0.3-93.7) IU/ml. One fresh cleavage-stage embryo was transferred in 37.4% (900/2408) of the initiated cycles. The overall clinical pregnancy rate and live birth rate per fresh embryo transfer were 2.8% (25/900) and 0.8% (7/900), respectively. Natural cycle IVF treatment led to seven successful deliveries during the period. All seven women who successfully delivered were poor ovarian responders who met the diagnostic Bologna criteria and, among them, three had elevated serum FSH levels on day 3 (range: 39.0-47.1 mIU/ml). All seven had full-term delivery, and no congenital abnormalities were observed in their infants. No significant difference was found in serum FSH level on day 3 between those with and without positive beta-HCG test results. CONCLUSIONS: These findings suggest that natural cycle IVF treatment could be an option for older poor responders in countries that do not permit egg donation. Careful counselling is required, however, because of the low probability of live births after IVF in middle-aged women.

Uterine leiomyosarcomas with osteoclast-like giant cells associated with high expression of RUNX2 and RANKL.

Uterine leiomyosarcoma (ULMS) with osteoclast-like giant cells (OLGCs) has been reported as a rare phenomenon in ULMS, and its clinico-pathological features and tumorigenesis remain unclear. We recently reported high expression of receptor activator of nuclear factor κB ligand (RANKL) in ULMS with OLGCs. As osteoblasts produce RANKL, in this study, we analyzed the expression of Runt-related transcription factor 2 (RUNX2), a critical transcription factor for osteoblasts, and osteoclast-related proteins in three cases of ULMS with OLGCs as well as five conventional ULMSs and nine leiomyomas. Immunohistochemistry and real-time reverse transcription quantitative polymerase chain reaction analyses showed high expression of RUNX2 and RANKL in ULMS with OLGCs. In these cases, macrophages expressed receptor activator of nuclear factor κB (RANK), and OLGCs expressed osteoclast-related proteins (nuclear factor of activated T cells, cytoplasmic 1 (NFATc1), and cathepsin K). Accumulation sites of cathepsin K-positive OLGCs showed hemorrhagic appearance and degraded type IV collagen. We reviewed reported cases of ULMS with OLGCs, including ours, and found that they presented an aggressive course even at stage I. Furthermore, metastatic lesions showed similar histological features to those of OLGC association in ULMS. Here, we show that tumor cells in ULMS with OLGCs highly express RUNX2 and RANKL and that osteoclastic differentiation of macrophages occurs in the tumor tissue.

Effectiveness and Long-term Outcomes of Nerve-Sparing Radical Hysterectomy for Cervical Cancer.

BACKGROUND: Radical hysterectomy (RH) is a type of radical surgery for cervical cancer. Urinary dysfunction due to RH worsens postoperative quality of life of patients with cervical cancer. Nerve-sparing RH (NSRH) technique has been used as an effective means to conserve urinary function. However, few reports have examine long-term outcomes after NSRH. This study describes the details and long-term outcomes of our nerve-sparing technique. METHODS: Sixty-one patients underwent radical hysterectomy in a 5-year period during which nerve-sparing technique was introduced; of these, 31 patients underwent NSRH and 30 underwent conventional RH. We retrospectively examined their medical records and compared postoperative urinary function and treatment outcomes between these two groups. RESULTS: The median time required for urinary residual volume to fall to ≤50 mL after removal of the urinary catheter was 6 days (range, 2-20 days) in the NSRH group and 13.5 days (range, 3-46 days) in the RH group. The results were significantly better in the NSRH group (p < 0.05). The mean follow-up period was 2456.3 days (range, 48-4,213 days). Analysis of curability revealed no significant difference between the two groups in local recurrence or long-term survival rates. The 5-year survival rate was 0.861 in the NSRH group and 0.782 in the RH group; the 10-year survival rate was 0.861 in the NSRH group and 0.679 in the RH group. CONCLUSIONS: NSRH significantly improved postoperative urinary function without worsening local recurrence rates or long-term outcomes.

Recent progress in the chemistry and biochemistry of strigolactones.

Strigolactones (SLs) are plant secondary metabolites derived from carotenoids. SLs play important roles in the regulation of plant growth and development in planta and coordinate interactions between plants and other organisms including root parasitic plants, and symbiotic and pathogenic microbes in the rhizosphere. In the 50 years since the discovery of the first SL, strigol, our knowledge about the chemistry and biochemistry of SLs has advanced explosively, especially over the last two decades. In this review, recent advances in the chemistry and biology of SLs are summarized and possible future outcomes are discussed.

Do Phosphate and Cytokinin Interact to Regulate Strigolactone Biosynthesis or Act Independently?

Strigolactones (SLs) are essential host recognition signals for both root-parasitic plants and arbuscular mycorrhizal (AM) fungi in the rhizosphere, and in planta SLs or their metabolites function as a novel class of plant hormones that regulate various aspects of plant growth through crosstalk with other hormones. Although nutrient availability is one of the important factors influencing SL production and exudation, and phosphate (Pi) deficiency significantly promotes SL production and exudation in host plants of AM fungi, how nutrient availability modulates SL production and exudation remains elusive. Cytokinin (CK), a canonical plant hormone, has extensively been studied as a shoot branching promoter and its biosynthesis is also influenced by mineral nutrients, especially nitrate, indicating that CK might be another key factor that affect SL production and exudation. In the present study, we show that CKs (t-zeatin, benzyladenine, kinetin, and CPPU) applied to hydroponic culture media significantly suppressed the SL levels in both the root exudates and the root tissues of rice plants grown under Pi deficiency. In a split-root system, CK suppressed SL production locally, while Pi affected SL production systemically, suggesting that Pi and CK act on SL production independently in rice plants.

Use of tumor markers to distinguish endometriosis-related ovarian neoplasms from ovarian endometrioma.

OBJECTIVE: Only few studies have focused on tumor markers used in the preoperative diagnosis of endometriosis-related ovarian neoplasms, and previous studies have only assessed serum CA125 levels. This study investigated the significance of preoperative tumor markers and clinical characteristics in distinguishing endometriosis-related ovarian neoplasms from ovarian endometrioma. METHODS: A case-control study was conducted on 283 women who were diagnosed with confirmed pathology with endometriosis-related ovarian neoplasms (n=21) and ovarian endometrioma (n=262) at a single institution from April 2008 to April 2018. The serum CA125, CA19-9, carcinoembryogenic antigen (CEA), sialyl Lewis-x antigen (SLX), and lactate dehydrogenase (LDH) levels, age, tumor size, and the presence of mural nodule of the patients were analyzed. RESULTS: Patients with endometriosis-related ovarian neoplasms were more likely to be older (48 (range, 26-81) vs 39 (range, 22-68) years, P<0.001), have higher levels of CA19-9 (42 vs 19 U/mL, P=0.013), CEA (1.3 vs 0.84 ng/mL, P=0.007), SLX (41 vs 33 U/mL, P=0.050), and LDH (189 vs 166 U/mL, P<0.001) and larger tumor size (79 vs 55 mm, P=0.001), and present with mural nodule (85.7 vs 4.5 %, P<0.001) than those with ovarian endometrioma. The CA125 levels did not significantly differ between the two groups. The area under the curve for each factor was as follows: CA19-9 level, 0.672 (95% CI 0.52 to 0.83; P=0.013); CEA level, 0.725 (95% CI 0.58 to 0.87; P=0.007); SLX level, 0.670 (95% CI 0.53 to 0.84; P=0.050); LDH level, 0.800 (95% CI 0.70 to 0.90; P<0.001); age, 0.775 (95% CI 0.65 to 0.90; P<0.001); and tumor size, 0.709 (95% CI 0.56 to 0.86; P=0.001). Age was a better marker than CA19-9, CEA, and SLX levels according to the receiver operating characteristic curve analysis. The optimal cut-off values for age and tumor size were 47 years and 80 mm, respectively. CONCLUSIONS: The assessment of serum CA19-9, CEA, SLX, and LDH levels may be a useful tool in the preoperative evaluation to differentiate between endometriosis-related ovarian neoplasms and ovarian endometrioma.

Hydroxyl carlactone derivatives are predominant strigolactones in Arabidopsis.

Strigolactones (SLs) regulate important aspects of plant growth and stress responses. Many diverse types of SL occur in plants, but a complete picture of biosynthesis remains unclear. In Arabidopsis thaliana, we have demonstrated that MAX1, a cytochrome P450 monooxygenase, converts carlactone (CL) into carlactonoic acid (CLA) and that LBO, a 2-oxoglutarate-dependent dioxygenase, can convert methyl carlactonoate (MeCLA) into a metabolite called [MeCLA + 16 Da]. In the present study, feeding experiments with deuterated MeCLAs revealed that [MeCLA + 16 Da] is hydroxymethyl carlactonoate (1'-HO-MeCLA). Importantly, this LBO metabolite was detected in plants. Interestingly, other related compounds, methyl 4-hydroxycarlactonoate (4-HO-MeCLA) and methyl 16-hydroxycarlactonoate (16-HO-MeCLA), were also found to accumulate in lbo mutants. 3-HO-, 4-HO-, and 16-HO-CL were detected in plants, but their expected corresponding metabolites, HO-CLAs, were absent in max1 mutants. These results suggest that HO-CL derivatives may be predominant SLs in Arabidopsis, produced through MAX1 and LBO.

Chemical identification of 18-hydroxycarlactonoic acid as an LjMAX1 product and in planta conversion of its methyl ester to canonical and non-canonical strigolactones in Lotus japonicus.

Strigolactones (SLs) are a group of plant apocarotenoids that act as rhizosphere signaling molecules for both arbuscular mycorrhizal fungi and root parasitic plants. They also regulate plant architecture as phytohormones. The model legume Lotus japonicus (synonym of Lotus corniculatus) produces canonical 5-deoxystrigol (5DS) and non-canonical lotuslactone (LL). The biosynthesis pathways of the two SLs remain elusive. In this study, we characterized the L. japonicus MAX1 homolog, LjMAX1, found in the Lotus japonicus genome assembly build 2.5. The L. japonicus max1 LORE1 insertion mutant was deficient in 5DS and LL production. A recombinant LjMAX1 protein expressed in yeast microsomes converted carlactone (CL) to 18-hydroxycarlactonoic acid (18-OH-CLA) via carlactonoic acid (CLA). Identity of 18-OH-CLA was confirmed by comparison of the methyl ester derivative of the MAX1 product with chemically synthesized methyl 18-hydroycarlactonoate (18-OH-MeCLA) using LC-MS/MS. (11R)-CL was detected as an endogenous compound in the root of L. japonicus.13C-labeled CL, CLA, and 18-OH-MeCLA were converted to [13C]-5DS and LL in plant feeding experiments using L. japonicus WT. These results showed that LjMAX1 is the crucial enzyme in the biosynthesis of Lotus SLs and that 18-hydroxylated carlactonoates are possible precursors for SL biosynthesis in L. japonicus.

The presence of amniotic fluid sludge in pregnant women with a short cervix: an independent risk of preterm delivery.

Objective: To examine whether the presence of amniotic fluid sludge (AFS) could increase the risk of preterm delivery in women with a cervical length (CL) of less than 25 mm.Materials and methods: This is a retrospective cohort study of 110 women who were 14-30 weeks pregnant with a singleton gestation and a CL of less than 25 mm. The primary outcomes were defined as preterm delivery before 34 weeks and preterm delivery before 37 weeks. The secondary outcome was defined as preterm premature rupture of membranes (PPROM) prior to preterm delivery. Risk factors for preterm delivery were defined as AFS, subchorionic hematoma (SCH), history of preterm delivery, CL of less than 20 mm, and CL of less than 15 mm. A univariate analysis was performed to assess the primary and secondary outcomes according to the presence or absence of each risk factor. A multiple logistic regression analysis was performed to evaluate the parameters, using a significance of p < .05 on the univariate analysis to examine whether they were independent risk factors.Results: A significantly increased risk of preterm delivery was found in the group of women with AFS who actually did deliver prior to 34 weeks (p < .001; odds ratio [OR] 6.44; 95% confidence interval [CI] 2.51-16.5), prior to 37 weeks (p = .001; OR 4.46; 95% CI 1.76-11.3), and who had PPROM (p < .001; OR 4.96; 95% CI 2.00-12.3). A multivariate logistic regression analysis was performed in the women with AFS who experienced preterm delivery before 34 weeks, in the women with a CL less than 20 mm, and in the women with a CL less than 15 mm. The results showed that AFS was an independent risk factor for preterm delivery before 34 weeks (p = .001; OR 5.86; 95% CI 2.11-16.3).Conclusion: The presence of AFS was an independent risk factor for preterm delivery before 34 weeks in women with a CL less than 25 mm.

Recurrence of uterine adenomyosis after administration of gonadotropin-releasing hormone agonist and the efficacy of dienogest.

This study elucidated the degree of adenomyosis recurrence following gonadotropin-releasing hormone agonist (GnRHa) discontinuation and dienogest efficiency for recurrent adenomyosis. This retrospective cohort study included 30 patients, divided into a group of patients whose progress was observed without providing additional therapy following GnRHa administration for six months (Group G) and a group of patients administered dienogest for six months following six months of GnRHa administration (Group D). Menorrhagia, dysmenorrhea, chronic pelvic pain, abdominal fullness, and uterine volume were recorded prior to treatment, six months after the start of therapy (6 M), and 12 months after the start of therapy (12 M). In Group G (n = 15), although all subjective symptoms disappeared at 6 M, nearly all symptoms recurred at 12 M. Uterine volume significantly decreased from 341.0 cm3 to 156.0 cm3 at 6 M (p = .001) and significantly increased again to 282.3 cm3 at 12 M (p = .003). In Group D (n = 15), all subjective symptoms disappeared at 6 M, and only abdominal fullness returned in a significant number of patients (5 of 5; p = .021) at 12 M. Uterine volume decreased significantly at 6 M (p = .003) and significantly increased again from 162.5 cm3 to 205.6 cm3 at 12 M (p = .006). Subjective symptoms, except for abdominal fullness, did not recur when dienogest was administered after GnRHa.

Genome Sequence of Striga asiatica Provides Insight into the Evolution of Plant Parasitism.

Parasitic plants in the genus Striga, commonly known as witchweeds, cause major crop losses in sub-Saharan Africa and pose a threat to agriculture worldwide. An understanding of Striga parasite biology, which could lead to agricultural solutions, has been hampered by the lack of genome information. Here, we report the draft genome sequence of Striga asiatica with 34,577 predicted protein-coding genes, which reflects gene family contractions and expansions that are consistent with a three-phase model of parasitic plant genome evolution. Striga seeds germinate in response to host-derived strigolactones (SLs) and then develop a specialized penetration structure, the haustorium, to invade the host root. A family of SL receptors has undergone a striking expansion, suggesting a molecular basis for the evolution of broad host range among Striga spp. We found that genes involved in lateral root development in non-parasitic model species are coordinately induced during haustorium development in Striga, suggesting a pathway that was partly co-opted during the evolution of the haustorium. In addition, we found evidence for horizontal transfer of host genes as well as retrotransposons, indicating gene flow to S. asiatica from hosts. Our results provide valuable insights into the evolution of parasitism and a key resource for the future development of Striga control strategies.

Exfoliation of Alveolar Rhabdomyosarcoma Cells in the Ascites of a 50-Year-Old Woman: Diagnostic Challenges and Literature Review.

Alveolar rhabdomyosarcoma (ARMS) is a nonepithelial tumor with skeletal muscle differentiation and typically affects adolescents and young adults. The cytological features of ARMS in body fluid have not been well characterized, which complicates diagnosis. Here, we describe the cytological features of ARMS in the ascites of a 50-year-old woman with an intra-abdominal mass and abundant ascites. Aspiration cytology of ascitic fluid revealed numerous small discohesive round cells with mild nuclear atypia and prominent nucleoli. Rhabdomyoblastic cells, characteristic of rhabdomyosarcoma, were identified rarely. Cannibalism and 'window' formation, as seen in reactive mesothelial cells, complicated the diagnosis of ARMS. Histological examination established the diagnosis of ARMS, which was confirmed by immunohistochemical expression of myogenic markers. When diagnosing ARMS from effusion samples, the diagnostic problems associated with the morphological similarity of ARMS cells to reactive mesothelial cells should be considered.