IL-6 secreted by cancer-associated fibroblasts induces tamoxifen resistance in luminal breast cancer

Cancer-associated fibroblasts (CAFs) have been implicated in the development of resistance to anticancer drugs; however, the role and mechanism underlying CAFs in luminal breast cancer (BrCA) tamoxifen resistance are unclear. We found that stromal fibroblasts isolated from the central or peripheral area of BrCA have similar CAF phenotype and activity. In vitro and in vivo experiments showed that CAFs derived from clinical-luminal BrCAs induce tamoxifen resistance through decreasing estrogen receptor-α (ER-α) level when cultured with luminal BrCA cell lines MCF7 and T47D. CAFs promoted tamoxifen resistance through interleukin-6 (IL-6) secretion, which activates Janus kinase/signal transducers and activators of transcription (JAK/STAT3) and phosphatidylinositol 3-kinase (PI3K)/AKT pathways in tumor cells, followed by induction of epithelial-mesenchymal transition and upregulation of E3 ubiquitin ligase anaphase-promoting complex 10 activity, which targeted ER-α degradation through the ubiquitin-proteasome pathway. Inhibition of proteasome activity, IL-6 activity or either the JAK/STAT3 or PI3K/AKT pathways markedly reduced CAF-induced tamoxifen resistance. In xenograft experiments of CAFs mixed with MCF7 cells, CAF-specific IL-6 knockdown inhibited tumorigenesis and restored tamoxifen sensitivity. These findings indicate that CAFs mediate tamoxifen resistance through IL-6-induced degradation of ER-α in luminal BrCAs.Oncogene advance online publication, 9 June 2014; doi:10.1038/onc.2014.158.

Improved search for ν¯(μ)→ν¯(e) oscillations in the MiniBooNE experiment

The MiniBooNE experiment at Fermilab reports results from an analysis of ν[over ¯](e) appearance data from 11.27×10(20) protons on target in the antineutrino mode, an increase of approximately a factor of 2 over the previously reported results. An event excess of 78.4±28.5 events (2.8σ) is observed in the energy range 200<E(ν)(QE)<1250 MeV. If interpreted in a two-neutrino oscillation model, ν[over ¯](μ)→ν[over ¯](e), the best oscillation fit to the excess has a probability of 66% while the background-only fit has a χ(2) probability of 0.5% relative to the best fit. The data are consistent with antineutrino oscillations in the 0.01<Δm(2)<1.0 eV(2) range and have some overlap with the evidence for antineutrino oscillations from the Liquid Scintillator Neutrino Detector. All of the major backgrounds are constrained by in situ event measurements so nonoscillation explanations would need to invoke new anomalous background processes. The neutrino mode running also shows an excess at low energy of 162.0±47.8 events (3.4σ) but the energy distribution of the excess is marginally compatible with a simple two neutrino oscillation formalism. Expanded models with several sterile neutrinos can reduce the incompatibility by allowing for CP violating effects between neutrino and antineutrino oscillations.

Improvement in transfusion safety using a specially designed transfusion wristband

Fatal haemolytic transfusion reaction due to ABO incompatibility occurs mainly as a result of clerical error. A blood sample drawn from the wrong patient and labelled as another patient's will not be detected by the blood bank unless there is a previous ABO grouping result. We report here the detection of such clerical error by the use of a specially designed transfusion wristband. The wristband has the following special features: (i) once attached, it cannot be removed except by cutting; (ii) it has a pocket containing a transfusion label; (iii) a unique transfusion barcode is printed on each transfusion label and the corresponding wristband simultaneously by computer technology; (iv) a transfusion label removed from the wristband after attachment to the patient has a characteristic tear-mark distinguishing it from one removed prior to attachment. The blood bank only accepted those specimens bearing the tear-marked transfusion labels. All blood units for this patient were labelled with this unique transfusion code together with the patient's details. The nurses counter-checked the transfusion code on the blood units against the transfusion code on the patient's transfusion wristband prior to transfusion. If the blood sample for compatibility testing was drawn from the 'wrong' patient, the intended patient either did not carry a wristband or the transfusion codes did not match at all. Pretransfusion compatibility tests were performed on 2189 patient samples using this procedure. It was well accepted by both ward and blood bank staff. Two potential mismatched transfusions were avoided. These two clerical errors would not have been detected because neither patient had previous ABO grouping results.

An epidemiologic study of irritable bowel syndrome in adolescents and children in South China: a school-based study

BACKGROUND

To explore the prevalence of irritable bowel syndrome (IBS) among school-aged children in South China, and identify distribution characteristics and contributing factors.

METHODS

Primary, middle and high school students (n= 2013) were recruited from schools in Shanghai. Students completed two questionnaires, one for IBS in adolescents and children and the Screen for Child Anxiety Related Emotional Disorders (SCARED).

RESULTS

(1) The prevalence of IBS among students was 20.72% and the incidence increased with age. (2) Several physical factors and overuse of analgesics were significantly associated with IBS. (3) The prevalence of anxiety disorder was higher in older students, and in females vs. males. Students with IBS tended towards anxiety-related emotional disorders (38.14% vs. 18.96%). (4) IBS students scored higher in all SCARED categories. Within IBS students, those who frequently sought medical care reported higher scores in the somatization/panic category.

CONCLUSION

(1) Irritable bowel syndrome is a common disorder among adolescents in South China and prevalence increases with age. (2) Gastrointestinal infection, abuse of analgesics and psychological factors might be related to the incidence of IBS. (3) The tendency towards anxiety-related emotional disorders also increases with age, suggesting a possible correlation with IBS and underlining the importance of positive family and school environments. Although the prevalence of anxiety-related emotional disorders was higher in females than males, this trend was not correlated with the occurrence of IBS.

AlaArg motif in the carboxyl terminus of the gamma(1)34.5 protein of herpes simplex virus type 1 is required for the formation of a high-molecular-weight complex that dephosphorylates eIF-2alpha

The gamma(1)34.5 protein of herpes simplex virus (HSV) type 1 functions to prevent the shutoff of protein synthesis mediated by the double-stranded-RNA-dependent protein kinase PKR. This is because gamma(1)34.5 associates with protein phosphatase 1 (PP1) through its carboxyl terminus, forming a high-molecular-weight complex that dephosphorylates the alpha subunit of translation initiation factor eIF-2 (eIF-2alpha). Here we show that Val193Glu and Phe195Leu substitutions in the PP1 signature motif of the gamma(1)34.5 protein abolished its ability to redirect PP1 to dephosphorylate eIF-2alpha and replication of mutant viruses was severely impaired. The gamma(1)34.5 protein, when expressed in Sf9 cells using a recombinant baculovirus, was capable of directing specific eIF-2alpha dephosphorylation. Deletions of amino acids 258 to 263 had no effect on activity of gamma(1)34.5. However, deletions of amino acids 238 to 258 abolished eIF-2alpha phosphatase activity but not PP1 binding activity. Interestingly, deletions in the AlaArg motif of the carboxyl terminus disrupted the high-molecular-weight complex that is required for dephosphorylation of eIF-2alpha. These results demonstrate that gamma(1)34.5 is functionally active in the absence of any other HSV proteins. In addition to a PP1 binding domain, the carboxyl terminus of gamma(1)34.5 contains an effector domain that is required to form a functional complex.

Significant Excess of Electronlike Events in the MiniBooNE Short-Baseline Neutrino Experiment

The MiniBooNE experiment at Fermilab reports results from an analysis of ν_{e} appearance data from 12.84×10^{20} protons on target in neutrino mode, an increase of approximately a factor of 2 over previously reported results. A ν_{e} charged-current quasielastic event excess of 381.2±85.2 events (4.5σ) is observed in the energy range 200<E_{ν}^{QE}<1250  MeV. Combining these data with the ν[over ¯]_{e} appearance data from 11.27×10^{20} protons on target in antineutrino mode, a total ν_{e} plus ν[over ¯]_{e} charged-current quasielastic event excess of 460.5±99.0 events (4.7σ) is observed. If interpreted in a two-neutrino oscillation model, ν_{μ}→ν_{e}, the best oscillation fit to the excess has a probability of 21.1%, while the background-only fit has a χ^{2} probability of 6×10^{-7} relative to the best fit. The MiniBooNE data are consistent in energy and magnitude with the excess of events reported by the Liquid Scintillator Neutrino Detector (LSND), and the significance of the combined LSND and MiniBooNE excesses is 6.0σ. A two-neutrino oscillation interpretation of the data would require at least four neutrino types and indicate physics beyond the three neutrino paradigm. Although the data are fit with a two-neutrino oscillation model, other models may provide better fits to the data.

Cl- channels are expressed in human normal monocytes: a functional role in migration, adhesion and volume change

Increased adhesion and diapedesis of monocytes appear to be primary initiating factors in the pathophysiology of occlusive vascular diseases, including atherosclerosis and restenosis. However, the underlying mechanisms of transendothelial migration and invasion of monocytes into the blood vessels are not known. Alterations in ion channels on the cell membrane are generally involved in induced changes in shape and volume. In the present study, we investigated the expression and functional role of chloride channels in freshly isolated human blood monocytes. The Cl- currents in whole-cells were measured by the patch-clamp technique. We observed whole cell Cl- currents, which were time-independent and outwardly rectifying. The chloride channel blockers 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) and R(+)-[(6,7-dichloro-2-cyclopentyl-2,3-dihydro-2-methyl-1-oxo-1H-inden-5yl)-oxy]acetic acid 94 (IAA94) attenuated the Cl- currents. NPPB and IAA94 also inhibited chemotaxis of monocytes, as measured in Boyden chemotactic chambers, with the same sensitivity. NPPB but not IAA94, increased the cell volume as measured by shape change, and decreased tumour necrosis factor (TNF)-alpha-induced monocyte adhesion to endothelial cells. These results suggest that monocytes contain Cl- channels which regulate transendothelial migration of monocytes, due presumably to an alteration in cell volume.

Targeted damage effects of high intensity focused ultrasound (HIFU) on liver tissues of Guizhou Province miniswine

HIFU can pass through tissues and accurately damage target tissues inside organisms. This article reports on the oriented damage effects of HIFU upon miniswine internal and external liver tissues, and suggests a new conception of the 'biological focal field'. The results revealed that: (1) HIFU can be used to damage accurately liver tissues under the guide of a B-modal ultrasound device; (2) the scope of the injury is connected with sound intensity and irradiation time; and (3) the different layers of tissue through which the ultrasound has passed remain undamaged.

A Schiff base is a major DNA adduct of crotonaldehyde

Previous studies have demonstrated that the reaction of crotonaldehyde with DNA produces Michael addition products, and these have been detected in human tissues as well as tissues of untreated laboratory animals. A second class of crotonaldehyde-DNA adducts releases 2-(2-hydroxypropyl)-4-hydroxy-6-methyl-1,3-dioxane (paraldol, 12) upon hydrolysis, and these adducts are quantitatively more significant than the Michael addition adducts in vitro. In this study, we demonstrate that the major source of the paraldol-releasing DNA adducts of crotonaldehyde is a Schiff base. Reaction of crotonaldehyde with DNA, followed by treatment with NaBH(3)CN and enzyme hydrolysis, resulted in the formation of N(2)-(3-hydroxybutyl)dG (10), identified by its UV, MS, and proton NMR. Reactions of crotonaldehyde or paraldol with dG demonstrated that the Schiff base precursor to N(2)-(3-hydroxybutyl)dG is N(2)-(3-hydroxybutylidene)dG (7), identified by UV, LC-APCI-MS, and MS/MS. Four isomers of N(2)-(3-hydroxybutylidene)dG were observed. The (R)- and (S)-isomers were identified by reactions of chiral paraldol with dG; each existed as a pair of interconverting (E)- and (Z)-isomers. These data indicate that the structure of the major Schiff base DNA adduct in crotonaldehyde-treated DNA is N(2)-(3-hydroxybutylidene)dG (7). This adduct is unstable at the nucleoside level and accounts for more than 90% of the paraldol released from crotonaldehyde-treated DNA. However, the adduct is stable in DNA and therefore is a likely companion to the Michael addition adducts in human DNA.

Mechanism of colchicine impairment on learning and memory, and protective effect of CGP36742 in mice

Fourteen days after hippocampal microinfusion with colchicine (COL), learning and memory ability of mice was significantly impaired, while glutamate (Glu), gamma-aminobutyric acid (GABA), Glu/GABAB and GABAB receptor levels in the cortex and/or the hippocampus were significantly changed. After treatment with a GABAB receptor antagonist, CGP36742, learning and memory impairment caused by COL could be significantly improved, and the above indices in brain regions reversed. These results suggest GABAB antagonists may have therapeutic value in the treatment of Alzheimer's disease.

Multi-objective optimization in radiotherapy: applications to stereotactic radiosurgery and prostate brachytherapy

Treatment planning for radiation therapy is a multi-objective optimization process. Here we present a machine intelligent scheme for treatment planning based on multi-objective decision analysis (MODA) and genetic algorithm (GA) optimization. Multi-objective ranking strategies are represented in the L(p) metric under the displaced ideal model. Goal setting, protocol satisficing and fuzzy ranking of objective importance can be incorporated into the decision scheme to assimilate clinical decision making. For distance measures in the L(p) metric, a dynamic gauge function is defined based on the state energy of the decision system, which is assumed to undergo thermodynamic cooling with iteration time. The MODA scheme interacts with a robust GA engine, which adaptively evolves in the multi-modal landscape that defines the treatment plan quality. A conventionally challenging case of stereotactic radiosurgery of a brain lesion was selected for GA optimization. The resulting dose distributions are compared to human-developed plans, which are commonly regarded as clinically relevant and empirically optimal. The GA-optimized plans achieve substantially better sparing of critical normal neuroanatomy surrounding the brain lesion while respecting the preset constraints on tumor dose uniformity. In addition, machine optimization tends to produce novel treatment strategies which complements expert knowledge. The run time for producing an optimal plan is considerably shorter than the typical planning time for human experts, thus GA can also be used to aid the human treatment planning process. In prostate brachytherapy, MODA-GA was specifically applied to non-ideal conditions in which typical surgical uncertainties in seed implant positioning occur, where noisy objectives were introduced into the optimization scheme. The noisy system is found to be manageable by MODA-GA at uncertainty levels corresponding to reasonably proficient surgery teams. In contrast, noisy objectives would be very difficult to explore by human expert planners. Potential use of noisy optimization with time series analysis is being explored for error-corrective computer guidance in the operating room for prostate seed implantation. In conclusion, the combination of MODA and GA optimization offers both a solution to practical treatment planning tasks and the potential for real time applications in radiotherapy.

Loss of p300 accelerates MDS-associated leukemogenesis

The role that changes in DNA methylation and histone modifications have in human malignancies is poorly understood. p300 and CREB-binding protein (CBP), two distinct but highly homologous lysine acetyltransferases, are mutated in several cancers, suggesting their role as tumor suppressors. In the current study, we found that deletion of p300, but not CBP, markedly accelerated the leukemogenesis ofNup98-HoxD13 (NHD13) transgenic mice, an animal model that phenotypically copies human myelodysplastic syndrome (MDS). p300 deletion restored the ability of NHD13 expressing hematopoietic stem and progenitor cells (HSPCs) to self-renew in vitro, and to expand in vivo, with an increase in stem cell symmetric self-renewal divisions and a decrease in apoptosis. Furthermore, loss of p300, but not CBP, promoted cytokine signaling, including enhanced activation of the MAPK and JAK/STAT pathways in the HSPC compartment. Altogether, our data indicate that p300 has a pivotal role in blocking the transformation of MDS to acute myeloid leukemia, a role distinct from that of CBP.

Molecular basis for Rh(null) syndrome: identification of three new missense mutations in the Rh50 glycoprotein gene

Rh(null) is a rare autosomal recessive disorder characterized by an absence of Rh antigens and a varying degree of hemolytic anemia and spherostomatocytosis. We report studies of two Japanese Rh(null) cases and describe three new missense mutations of RHAG, the locus that encodes Rh50 glycoprotein and modulates Rh antigen expression. In Rh(null)(HT), RHAG harbored in exon 6 two G-->A transitions, GTT-->ATT and GGA-->AGA, which cause Val(270)-->Ile and Gly(280)-->Arg substitutions, respectively. These missense mutations were cotransmitted from the propositus to the children and were predicted to reside in endoloop 5 and transmembrane (TM) segment 9, respectively. In Rh(null)(WO), RHAG contained in exon 9 a single G-->T transversion, GGT-->GTT, which caused a Gly(380)-->Val missense change in TM12 segment. The G-->T transversion, which is located at the +1 position of exon 9, had also affected pre-mRNA splicing and caused partial exon skipping. Although both Rh(null) cases had a structurally normal RH antigen locus, hemagglutination and immunoblotting showed no expression of Rh antigens or proteins. These results correlate each mutation with a structural defect in the respective TM domain of Rh50 glycoprotein.

Independent effect of vitamin B12 deficiency on hematological status in older Chinese vegetarian women

We have examined the independent effect of vitamin B(12) deficiency on hematological indices in older Chinese vegetarian women using a cross-sectional study design: 119 women older than 55 years who had been vegetarian for more than 3 years were studied. Fasting blood samples were taken for complete blood count, serum iron, total serum iron binding capacity, serum iron saturation, serum vitamin B(12), serum folate, serum methylmalonic acid levels (MMA), and renal function test. Subjects with iron deficiency (iron saturation <15%) and those with serum creatinine >150 mmol/L were excluded. The prevalence of definite vitamin B(12) deficiency (vitamin B(12) level < 150 pmol/L and MMA >or= 0.4 micromol/L) was 42%. Another 32.8% had possible vitamin B(12) deficiency (either criterion). The prevalence of iron deficiency was 10%. After exclusions, 96 subjects were further analyzed. Vitamin B(12) deficiency defined by serum vitamin B(12) and MMA was associated with a decrease in hemoglobin concentrations by up to 0.9 g/dL, but it was not associated with an increase in mean corpuscular volume (MCV). Serum MMA but not vitamin B(12) levels correlated inversely with hemoglobin and platelet counts and positively with MCV, after adjustment of confounding factors. However, the percentage of subjects with anemia did not increase significantly until serum MMA became >1.0 micromol/L. In conclusion, vitamin B(12) deficiency was associated with a significant decrease in hemoglobin concentration. However, anemia associated with vitamin B(12) deficiency was seldom macrocytic. We recommend that older vegetarians should be given vitamin B(12) supplements routinely.

Identification of paraldol-deoxyguanosine adducts in DNA reacted with crotonaldehyde

Crotonaldehyde (1) is a mutagen and carcinogen, but its reactions with DNA have been only partially characterized. In a previous study, we found that substantial amounts of 2-(2-hydroxypropyl)-4-hydroxy-6-methyl-1,3-dioxane (paraldol, 7), the dimer of 3-hydroxybutanal (8), were released upon enzymatic or neutral thermal hydrolysis of DNA that had been allowed to react with crotonaldehyde. We have now characterized two paraldol-deoxyguanosine adducts in this DNA: N(2)-[2-(2-hydroxypropyl)-6-methyl-1,3-dioxan-4-yl]deoxyguanosine (N(2)-paraldol-dG, 13) and N(2)-[2-(2-hydroxypropyl)-6-methyl-1, 3-dioxan-4-yl]deoxyguanylyl-(5'-3')-thymidine [N(2)-paraldol-dG-(5'-3')-thymidine, 14]. Four diastereomers of N(2)-paraldol-dG (13) were observed. Their overall structures were determined by (1)H NMR, by MS, and by reaction of paraldol with deoxyguanosine and DNA. (1)H NMR data showed that two diastereomers had all equatorial substituents in the dioxane ring, while two others had an axial 6-methyl group. Preparation of paraldol with the (R)- or (S)-configuration at the 6-position of the dioxane ring and the carbinol carbon of the 2-(2-hydroxypropyl) group allowed partial assignment of the absolute configurations of N(2)-paraldol-dG (13). Four diastereomers of N(2)-paraldol-dG-(5'-3')-thymidine (14) were observed. Their overall structure was determined by (1)H NMR, MS, and hydrolysis with snake venom or spleen phosphodiesterase. Reactions of nucleosides and nucleotides with paraldol demonstrated that adducts were formed only from deoxyguanosine and its monophosphates. Experiments with DNA that had been reacted with crotonaldehyde indicated that N(2)-paraldol-dG-containing adducts in DNA are relatively resistant to enzymatic hydrolysis. The results of this study demonstrate that the reaction of crotonaldehyde with DNA is more complex than previously recognized and that stable N(2)-paraldol-dG adducts are among those that should be considered in assessing mechanisms of crotonaldehyde mutagenicity and carcinogenicity.

Vitamin B12 deficiency--need for a new guideline

OBJECTIVES

Many patients with vitamin B12 deficiency do not have anemia or macrocytosis, but the prevalence of B12 deficiency in patients without macrocytosis is not known.

METHODS

We investigated the prevalence of B12 deficiency among patients with normocytosis and microcytosis and recommended a screening strategy. All patients (n = 3714) with serum B12 measured at the Prince of Wales Hospital in 1996 were reviewed. The prevalence of serum B12 less than 140 pmol/L was determined for the following patient subgroups: younger than 70 y, older than 70 y, anemic, non-anemic, macrocytic, normocytic, microcytic, documented iron deficiency, and documented thalassemia.

RESULTS

The prevalence of B12 deficiency (<140 pmol/L) ranged from 4.8% to 9.8% among the different subgroups.

CONCLUSIONS

Whatever screening criteria were used, a significant number of B12-deficient patients will be missed. Therefore, there may be a case for universal vitamin B12 screening.

Effect of axial ligation and delivery system on the tumour-localising and -photosensitising properties of Ge(IV)-octabutoxy-phthalocyanines

Four Ge(IV)-octabutoxy-phthalocyanines (GePcs) bearing two alkyl-type axial ligands were assayed for their pharmacokinetic properties and phototherapeutic efficiency in Balb/c mice bearing an intramuscularly transplanted MS-2 fibrosarcoma. The GePcs were i.v. injected at a dose of 0.35 mumol kg-1 body weight after incorporation into either Cremophor emulsions or small unilamellar liposomes of dipalmitoyl-phosphatidylcholine (DPPC). Both the nature of the delivery system and the chemical structure of the phthalocyanine were found to affect the behaviour of the GePcs in vivo. Thus, Cremophor-administered GePcs invariably yielded a more prolonged serum retention and a larger association with low-density lipoproteins (LDLs) as compared with the corresponding liposome-delivered phthalocyanines. This led to a greater efficiency and selectivity of tumour targeting. These effects were more pronounced for those GePcs having relatively long alkyl chains (hexyl to decyl) in the axial ligands. Maximal tumour accumulation (0.67 nmol per g of tissue) was found for Ge-Pc(hexyl)2 at 24 h after injection. Consistently, the Ge-Pc(hexyl)2, administered via Cremophor, showed the highest phototherapeutic activity towards MS-2 fibrosarcoma.

Study of enzymatic digestion of cellulose by small angle neutron scattering

Small angle neutron scattering (SANS) was used to study the structure of Avicel (FD100) microcrystalline cellulose during enzymatic digestion. Digestions were performed in either of two modes: a static, quiescent mode or a dynamic mode using a stirred suspension recycled through a flow cell. The scattering pattern for as-received Avicel in D(2)O buffer is comprised of a low Q power law region resulting from the surface fractal character of the microcrystalline fibers and a high Q roll-off due to scattering from water-filled nanopores with radii approximately 20 A. For digestions in the dynamic mode the high Q roll-off decreased in magnitude within approximately 1 h after addition of enzymes, whereas in the static digestions no change was observed in the high Q roll-off, even after 60 h. These results indicate that only with significant agitation does enzyme digestion affect the structure of the nanopores.

Suppressive effects of SP-A on ionomycin-induced IL-8 production and release by eosinophils

Recent studies have demonstrated that pulmonary surfactant protein (SP)-A plays a potential role in modifying inflammation and immune function. To see whether SP-A could modify IL-8 production and release by eosinophils stimulated with ionomycin, SP-A purified from surfactant recovered from patients with alveolar proteinosis was added to eosinophils isolated by the negative-selection method with immunomagnetic beads, and cultured for 24 h. The concentrations of IL-8 in the cell-free supernatants and cell lysates were then measured by ELISA. SP-A attenuated the production of IL-8 by eosinophils in a concentration-dependent manner. SP-A also attenuated the release of IL-8 from the eosinophils. The addition of SP-A antibody (PE10) reversed these effects of SP-A completely. These data suggest that SP-A may have the potential to modify allergic inflammation by inhibiting the release and production of IL-8 by eosinophils.

Recurrent keratocystic odontogenic tumours: report of 19 cases

OBJECTIVES

The aim of this study was to analyse 19 recurrent keratocystic odontogenic tumours (KCOTs).

METHODS

19 patients with recurrent KCOTs were retrospectively analysed. These patients had been treated by either enucleation or a combination of enucleation and Carnoy's solution. The analyses covered major aspects of primary KCOT and/or recurrent KCOT identities, including patient profile, clinical features, histopathology, radiology, treatment and prognosis.

RESULTS

19 (7.4%) out of 257 primary KCOT cases recurred, with an average patient age of 30.5 years (age range 18-45 years). 15 lesions were in the mandible and the remaining 4 were in the maxilla. There were more unilocular than multilocular occurrences for the primary tumours, with a ratio of 2.2:1. These KCOTs were initially treated by simple enucleation (12 cases) or enucleation with Carnoy's solution (7 cases). After the initial surgery, 15 out of 19 (78.9%) recurred within 6 years, while 4 (21.1%) recurred after 6 years. Evidently, the recurrent lesion was involved with the roots of the teeth in three out of six cases whose teeth were preserved. In addition, the recurrent KCOTs had a tendency to be more multilocular or multifocal than the primary cases, with a unilocular-to-multilocular ratio of 1.1:1.

CONCLUSIONS

7.4% of primary KCOTs recurred within 6 years after initial treatment with either enucleation or a combination of enucleation and Carnoy's solution. The recurrent KCOTs were more likely to be multilocular or multifocal than the primary cases and often involved the teeth. The method of operation for these recurrent lesions would be considered as a more aggressive approach.