RESUMO
Clinically, 4-8 Hz (or 30-80 Hz) stimulation of the caudate nucleus ceases (or enhances) the neocortical and hippocampal epileptiform activities of the epilepsy patients. Possibly, electric stimulation of the caudate nucleus could produce epilepsy. In order to prove this point we delivered the acute tetanization (60 Hz, 2s, 0.4-0.6 mA) into the rat right caudate putamen nucleus (ATRC) and examined bilateral neocortical EEG and hippocampal unit discharges in vivo. The results demonstrated that: (1) 80-280 Hz EEG ripples could be evoked bilaterally, and more stronger on the contralateral side. And the maximum amplitudes of the power spectra (microV2/Hz) have higher shifting variability among multiple contralateral EEG ripples. (2) The EEG ripples were coupled contralaterally with the hippocampal neuronal firing inhibition. (3) An episode of 10-15 Hz EEG oscillations was ipsilaterally coupled with rhythmic hippocampal neuronal bursts. It suggested that the hemispheric reactions of neocortical EEG and hippocampal neuronal discharges are lateralized in response to the stimulation. It implies that the epileptic network activities were reorganized by the ATRC. Neocortical EEG ripples, called as seizure-like fast oscillations, were repetitively evoked by the ATRC.
Assuntos
Núcleo Caudado/fisiopatologia , Eletroencefalografia , Epilepsia/patologia , Putamen/fisiopatologia , Transmissão Sináptica/fisiologia , Animais , Modelos Animais de Doenças , Estimulação Elétrica , Eletrofisiologia , Potenciais Evocados , Hipocampo , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
The purpose of the present work was to study the effect of acute tetanization of the right caudate putamen nucleus (ATRC) on single neuronal interspike intervals (ISIs) in both laterodorsal thalamic nuclei (LDi), and electroencephalogram (EEG) wave interpeak intervals (IPIs) in both hippocampi (HPCi). Experiments were performed on 21 male Sprague-Dawley rats weighing 150~250 g. The seizures were induced by the ATRC (60 Hz, 2 s, 0.4~0.6 mA). Quadruple recordings were simultaneously carried out: two for single unit recordings from both LDi, and two for EEG recordings from both HPCi. The ATRC induced: (1) An interactive epileptic electrical network reconstructed in bilateral HPCi, which was driven by primary afterdischarges of single LD neuron. (2) A symmetric mirror-like ISI spot distribution of the LD neuronal firing before and after tetanus. (3) Gradually prolonged LD neuronal discharge intermittence was coherent with synchronous hippocampal EEG activities on the contralateral side. (4) Single LD neuronal spikes were phase- and time-locked to 20~25 Hz gamma oscillations in contralateral HPC. It suggests a particular temporal code patterning of single LD neuronal firing and its relationships to hippocampal EEG wave code in time series, the latter implies the LD neuronal encoding mechanisms of ATRC-induced epileptic electrical network in bilateral HPCi.
Assuntos
Núcleo Caudado/fisiologia , Eletroencefalografia , Hipocampo/fisiologia , Núcleos Laterais do Tálamo/fisiologia , Rede Nervosa/fisiologia , Potenciais de Ação/fisiologia , Animais , Estimulação Elétrica/métodos , Epilepsia/etiologia , Epilepsia/fisiopatologia , Masculino , Neurônios/fisiologia , Ratos , Ratos Sprague-Dawley , Tempo de Reação/fisiologiaRESUMO
The purpose of the present work was to study the role of unilateral hippocampal neural network in hippocampal epileptogenesis and its cellular mechanisms. Experiments were performed on 45 Sprague-Dawley adult rats. Acute tetanization (60 Hz, 2 s, 0.4 - 0.6 mA) of the right posterior dorsal hippocampus (ATPDH) was used to induce hippocampal epilepsy. The single unit discharges and the depth electrographs were synchronously recorded with a glass microelectrode and a pair of stainless concentric electrodes in the ipsilateral anterior dorsal hippocampus (HPC). The results demonstrated that: (1) some primary unit after-discharges were synchronized with electrographic after-discharges in the anterior dorsal HPC network after eight or nine tetanic trains were administered. Others desynchronized with 5 - 90 Hz primary depth electrographic after-discharges; (2) primary electrographic after-discharges were driven by primary unit after-discharges in the anterior dorsal HPC; (3) primary unit after-discharges were induced by brief primary electrographic after-discharges; and (4) plasticity of primary electrographic after-discharges and inhibition of single neuron firing were induced by repetitive ATPDH. The results suggest that hippocampal pathophysiologic network along the temporal-septal axis of the HPC is re-established by the repetitive ATPDH. There are plastic interactions between single neurons and its network during this re-establishment, which may be involved in the generation of "seizure oscillation". Over-activation of an intrinsic inhibition of the HPC along its temporal-septal axis might be involved in hippocampal network epileptogenesis.
Assuntos
Epilepsia do Lobo Temporal/fisiopatologia , Hipocampo/fisiopatologia , Rede Nervosa/fisiopatologia , Animais , Estimulação Elétrica , Potenciais Evocados , Masculino , Neurônios/fisiologia , Ratos , Ratos Sprague-DawleyRESUMO
The purpose of this work was to study the characteristics of rat brain abnormalities at two hemispheres at the early stage of electrogenic epilepsy. Experiments were performed on 37 male Sprague-Dawley rats. Chronically repetitive tetanization (60 Hz, 2 s, 0.4 - 0.6 mA) was used to stimulate the right dorsal hippocampus (DHPC) of the rat brain once a day for 2, 4, 6, 8 or 10 d, respectively. The T(2) weighted magnetic resonance image (T(2)-WI) were obtained from each experimental rat at the end of the experiments. Histological sections were obtained after experimentation. The results showed that the main pathologic changes at the early stage of epilepsy included: (1) T(2)-WI hyperintensification, the histological enlargement of lateral ventricle (LV) and pathological hyperplasia of ventricular choroidea plexus occurred. The pathological hyperplasia was symmetric in two hemispheres, but the LV enlargement was not. (2) Histologically enlarged LV area showed a resemblance to T(2)-WI hyperintensive area. Compared with the control rats, large T(2)-WI hyperintensive area (P=0.0259; P=0.0184; P=0.0184; P=0.0404; P=0.0259) and histologically enlarged LV area (P=0.0210; P=0.01; P=0.0100; P=0.0152) were present in chronically tetanized rats. (3) Dynamic characteristics of histologically enlarged LV area resembled to those of T(2)-WI hyperintensity area in chronically tetanized rats at different stimulating day. Lateralization of T(2)-WI hyperintensity was in accordance with that of T(2)-WI abnormal area and of histologically enlarged LV. These abnormalities were severe on the contralateral side on the stimulating day 6, or on the ipsilateral side on the stimulating day 10. These results imply characteristic propagation of brain abnormalities crossing to the opposite hemisphere at the early stage of an electrogenic rat epilepsy.
Assuntos
Córtex Cerebral/patologia , Epilepsia/patologia , Epilepsia/fisiopatologia , Hipocampo/fisiopatologia , Animais , Córtex Cerebral/fisiopatologia , Estimulação Elétrica , Epilepsia/etiologia , Imageamento por Ressonância Magnética , Masculino , Ratos , Ratos Sprague-Dawley , Fatores de TempoRESUMO
The purpose of the present study was to investigate the features of pathophysiological neural networks in rat temporal lobe epileptogenesis. To establish electrogenic epilepsy model, repetitive tetanization (60 Hz, 2 s, 0.4-0.6 mA) was delivered into the right dorsal hippocampus (HPC) of rat brain. Rats were divided into different groups. Experimental animals received tetanic stimulation once a day for 2, 4, 6, 8 or 10 days, respectively. Primary wet dog shakes (WEDS) of the animals were recorded daily during the stimulation to understand the development of behavioral seizures at early stage of epilepsy. The T(2)-weighted (T(2)-WI) spin-echo images were obtained from each experimental rat. The results demonstrated that T(2)-WI hyperintensity of experimental rats was observed in bilateral symmetric dorsal lateral ventricle (LV) areas at stimulating day 2 (n=4), in contralateral medial and ventral LV areas to the side of the electrode at stimulating day 6 (n=5), in contralateral ventral LV areas at stimulating day 8 (n=3), and in ipsilateral ventral LV areas at stimulating day 10 (n=4). Therefore the peak rate of primary WEDS appeared on stimulating day 4 in the experimental rats. Morphological identification demonstrated that the T(2)-WI signal abnormalities were related to the enlarged LV and pathological ventricular choroidea plexus hyperplasia. The results suggest that the development of rat brain abnormalities from dorsal LV to ventral LV at early stage of epilepsy can be measured by magnetic resonance image, which implies reorganization of pathophysiologically functional networks before kindling effect appear.
Assuntos
Encéfalo/fisiopatologia , Epilepsia do Lobo Temporal/diagnóstico , Imageamento por Ressonância Magnética , Animais , Progressão da Doença , Epilepsia do Lobo Temporal/patologia , Técnicas In Vitro , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
Angiopoietins are endothelial growth factors, which play crucial roles in normal vascular development and tumor angiogenesis. We examined the expression profiles of angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), vascular endothelial growth factor (VEGF), and Tie-2, a receptor for Ang-1 and Ang-2, in both colorectal adenocarcinoma and adjacent normal tissues, as judged by histology, in order to elucidate their relationships with microvascular density (MVD) and clinicopathologic properties. Higher MVD was associated with a lower degree of differentiation of colorectal adenocarcinoma. Immunohistochemical analysis revealed that the expression of Ang-2 and VEGF was significantly increased in colorectal adenocarcinoma compared to adjacent normal tissues (p < 0.01), and the expression of Ang-2 positively correlated with that of VEGF (r = 0.997, p < 0.01). In contrast, the expression of Ang-1 was lower in adenocarcinoma tissues than in adjacent normal tissues (p < 0.01), while there was no significant difference in Tie-2 expression in both tissues. Moreover, MVD was increased in Ang-2- and VEGF-expressing adenocarcinoma tissues compared to the Ang-2- and VEGF-negative tissues, respectively (p < 0.01). Importantly, MVD was lower in Ang-1-expressing adenocarcinoma tissues relative to Ang-1-negative tissues (p < 0.01). Furthermore, expression of Ang-2 as well as VEGF was significantly up-regulated in colorectal adenocarcinoma with diameters > or = 5 cm or with lymph-node metastases (p < 0.01). In conclusion, the increased expression of Ang-2 and the decreased expression of Ang-1 may be responsible for blood vessel formation and rapid growth of the colorectal adenocarcinoma.
Assuntos
Adenocarcinoma/irrigação sanguínea , Angiopoietina-2/metabolismo , Neoplasias Colorretais/irrigação sanguínea , Neovascularização Patológica/patologia , Adenocarcinoma/genética , Adenocarcinoma/patologia , Adenocarcinoma/cirurgia , Adulto , Idoso , Angiopoietina-1/metabolismo , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Neoplasias Colorretais/cirurgia , Feminino , Humanos , Imuno-Histoquímica , Masculino , Microcirculação/patologia , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Receptor TIE-2/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
AIM: To study the characteristics of neural information encoding of the epileptic networks involved caudate-putamen(CPu) and the hippocampi induced by tetanization of the right CPu in rats. METHODS: Experiments were performed on 59 SD rats. Acute or chronic tetanization of the right CPu (ATRC or CTRC) (60Hz,0.4-0.6 mA, 2 s) was used to induce rat epilepsy. RESULTS: (1) The bursting or primary unit afterdischarges of single neurons were asymmetric in dual hippocampi induced by the ATRC. (2) Continuous sharp waves were observed in ipsilateral or contralateral CPu induced by the CTRC. The oscillatory network seizures with phase shift appeared between two sharp waves in ipsilateral CPu. The frequency of oscillatory waves was negatively correlated with the time and fluctuated from 70 Hz to 110 Hz, then to 35 Hz, and finally to 30 Hz. (3) In the contralateral side primary network after discharges in the CPu were induced by the CTRC. Therefore, the characteristic primary network afterdischarges could be shifted from the CPu or to the HPC, but amplified. On the other hand, HPC sharp waves could be depressed when the CPu network seizures occurred. CONCLUSION: The reestablishment of CPu-hippocampal epileptic networks could be transhemispherically promoted by over-activation of the right CPu network, in which bilateral hippocampal neuronal network and CPu neural network were involved in some particular pathophysiological information encoding.
Assuntos
Núcleo Caudado/metabolismo , Epilepsia/fisiopatologia , Hipocampo/metabolismo , Animais , Masculino , Neurônios/metabolismo , Putamen/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
AIM: To investigate the regulatory network of hippocampal-systemic arterial blood pressure during epileptic network reestablishment. METHODS: 7.2 microg picrotoxin (PTX) was microinjected into the right HPC (RHPC) to induce rat epilepsy. Contralateral hippocampal EEG, single unit discharges, femoral artery blood pressure and ECG were recorded simultaneously. RESULTS: PTX might induce: (1) A resemblance interspike intervals (ISI) spot distribution of long duration neuronal burst and unit after discharges in contralateral HPC. (2) Delayed the initiation time of hippocampal neuronal bursts coupled with arterial blood pressure depression. (3) Hippocampal neuronal burst or unit after discharges coupled complexly with arterial blood pressure depression. (4) Resemblance hippocampal EEG interpeak intervals (IPI) and neuronal firing ISI spot distribution coupled with arterial blood pressure depression. CONCLUSION: During contralateral hippocampal epileptic network reestablishment after microinjection of PTX to the RHPC, the function of the hippocampal-arterial blood pressure regulatory network could be modulated by characteristic network and neuronal temporal code patterning.
Assuntos
Pressão Sanguínea/fisiologia , Epilepsia/fisiopatologia , Hipocampo/fisiologia , Hipocampo/fisiopatologia , Animais , Eletrocardiografia , Eletroencefalografia , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
AIM: To study the role of epileptic neural networks reestablished in contralateral caudate putamen (CPu)-hippocampus(HPC) by using chronic tetanization of the right corpus callosum (CTRCC). METHODS: Experiments were performed on 50 SD rats under anaesthesia. The left CPu (LCPu) and the left HPC(LHPC) electrographs were synchronously recorded after acute tetanization following CTRCC (60 Hz, 0.4-0.6 mA, 2 s). RESULTS: (1) In contralateralization to the side implanted interconvertible network inhibition between the CPu and the HPC were induced by combinedly using chronic and acute tetanization of the RCC. (2) Electrographic kindling in the LCPu or in the LHPC was recorded after CTRCC. (3) In case the LCPu or the LHPC electrographs were not kindled after CTRCC, hypsarrhythmia in the LCPu and reduced sharp waves in the HPC were induced b y repetitive tetanization of the RCC once again. Primary afterdischarges in the LCPu or in the LHPC electrographs were evoked by combinedly using chronic and acute tetanization of the RCC. CONCLUSION: Pathophysiological neural networks in the CPu and in the HPC might be reestablished in another side of hemispheres by chronic over-activation of the right CC, which is related to epileptogenesis. Abnormal interactions between the two functional neural networks might be involved in formation of secondary epileptic focus.
Assuntos
Núcleo Caudado/fisiopatologia , Corpo Caloso/patologia , Epilepsia/patologia , Hipocampo/fisiopatologia , Rede Nervosa , Animais , Núcleo Caudado/patologia , Corpo Caloso/fisiopatologia , Modelos Animais de Doenças , Estimulação Elétrica , Epilepsia/fisiopatologia , Hipocampo/patologia , Masculino , Putamen/patologia , Putamen/fisiopatologia , Ratos , Ratos Sprague-DawleyRESUMO
AIM: The electrographic and behavioral kindling effects were induced by chronic tetanization of the right caudate-putamen (CPu) to study the target-behavior expression involved in the CPu or hippocampus (HPC) network abnormalities. METHODS: Experiments were performed on 58 SD rats. Tetanization (60Hz,0.4 - 0.6mA, 2s) was delivered into the CPu or the HPC, once a day, for 7-12 days. Animal behaviors were observed every day and depth electrographs were recorded at the beginning or at the end of the experiments. RESULTS: Chronic tetanization of the CPu or of the HPC induced: (1) Rhythmic sharp waves in the CPu and paroxysmal epileptiform events in the HPC electrographs. (2) Primary behavioral seizures, secondary behavioral seizures, and kindling effects, including wet dog shakes (WEDS), rearing, face washing, immobility, chewing and head nodding. (3) Lower rate of primary WEDS (P < 0.01), and higher rate of secondary WEDS (P < 0.01) in the CPu-tetanized rats. (4) Longer silent period of behavioral seizures before kindling appeared in the CPu-tetanized rats. CONCLUSION: Kindling effects in the CPu-tetanized rats resembles those in the HPC-tetanized rats. The CPu might participate in the origin of epileptic focus and be involved in reestablishment of limbic epileptic networks, which may be responsible for the target-behavioral seizures.
Assuntos
Epilepsia/fisiopatologia , Excitação Neurológica , Convulsões/fisiopatologia , Animais , Comportamento Animal , Núcleo Caudado , Estimulação Elétrica , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
AIM: To investigate the neural network and cellular mechanisms of hippocampal epileptogenesis contralateral or ipsilateral to the side of acute tetanization (60 Hz, 2 s, 0.4 - 0.6 mA) of the posterior dorsal hippocampus (ATPDH). METHODS: 10 trains of the ATPDH were administered into the CA1 basal dendritic region of the right hemisphere at an interval of 10 minutes. RESULTS: (1) The firing rate of CA1 single neuron in the right or the left hippocampus was inhibited respectively after the ATPDH, and the effects weakened gradually while the trains of the ATPDH increased. The inhibited firing rate and the transformed firing pattern from tonic one to clonic one were more obvious at the side contralateral to the stimulation (62.94% +/- 3.68%, 36.61% +/- 3.14%, P < 0.01). (2) Synchronous primary afterdischarges of depth EEG and single unit discharges were more commonly observed at the side ipsilateral to the ATPDH (P < 0.01). (3) Primary or secondary hippocampal network afterdischarges at high frequency were only found in CA1 region ipsilateral to the ATPDH. (4) Secondary afterdischarges of CA3 basal dendritic neural network were completely synchronized with those of subicular single neuron, which reoccurred and persisted several hours. CONCLUSION: It is possible that post-inhibition bursting of single neuron and recurrent network seizures in the hippocampus contralateral to the artificial focus be the important manifestation of the formation of "epileptic networks" across from one hemisphere to another.
Assuntos
Hipocampo/fisiologia , Vias Neurais/fisiologia , Convulsões/etiologia , Animais , Estimulação Elétrica , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
BACKGROUND & OBJECTIVE: Recent studies revealed a possible close association between the expression of some members of tumor-specific antigen MAGE (melanoma antigen) family and actively proliferated infantile cells. But the correlation of MAGE-A1 expression with proliferation of tumor cells and immune response at host local site has not been reported to date. Our study was to investigate the expression of MAGE-A1 in non-small cell lung carcinoma (NSCLC), and its relationship with Ki-67 expression, tumor-infiltrating lymphocyte (TIL) response, histologic grade, and pathological type. METHODS: Thirty NSCLC samples in formalin-fixed, paraffin-embedded sections were examined for MAGE-A1, Ki-67 and TIL response using SP immunohistochemical technique. RESULTS: The positive expression rate of MAGE-A1 was 80.00%(24/30) with high expression rate of 58.33%(14/24) and low expression rate of 41.67%(10/24). The positive expression rate of Ki-67 was 93.33%(28/30) with high expression rate of 57.14%(16/28) and low expression rate of 42.86% (12/28). TIL response was observed in 22 patients. There was a significant relationship between MAGE-A1 positive expression and Ki-67 positive expression (rs=0.578, P< 0.005), as well as between MAGE-A1 positive expression and TIL response (rs=0.505, P< 0.005). However, MAGE-A1 expression was not significantly correlated with histologic grade and pathological type (P >0.05). CONCLUSION: The NSCLC cells with MAGE-A1 positive expression possess high proliferation activity; meanwhile, the up-regulation of MAGE-A1 indicates the increase of antigen in tumor cells and the increase of local TIL response, indicating that MAGE-A1 may have potential to be used as a target for immunotherapy in NSCLC patient.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/imunologia , Antígeno Ki-67/análise , Neoplasias Pulmonares/imunologia , Linfócitos do Interstício Tumoral/imunologia , Proteínas de Neoplasias/análise , Adulto , Idoso , Antígenos de Neoplasias , Carcinoma Pulmonar de Células não Pequenas/patologia , Feminino , Humanos , Neoplasias Pulmonares/patologia , Masculino , Antígenos Específicos de Melanoma , Pessoa de Meia-Idade , Estadiamento de NeoplasiasRESUMO
BACKGROUND & OBJECTIVE: There is evidence that cyclooxygenase-2(COX-2) involved in the occurrence and development of neoplasms. Elevated expression of COX-2 in carcinomas and antitumor effects of nonsteroidal antiinflammatory drug(COX-2 inhibitors) have been reported, but COX-2 expression in precancerous lesions and its association with angiogenesis is not clearly defined. The aim of this study was to investigate the expression of COX-2 protein and its association with microvessel density (MVD) during the experimental rat lung carcinogenesis. METHODS: Eighty Wistar rats were intra-leftlobar-bronchial instilled with 3-methylcholanthrene and diethylinitrosamine to induce lung squamous cell carcinoma, and ten rats were instilled lipiodol as control group. To acquire every pathological phase during the carcinogenesis, rats were sacrificed at intervals from fifteen days to nine months. COX-2 expression and MVD count in the samples of every pathological phase during the carcinogenesis were examined by immunohistochemistry. The immunohistochemical score of COX-2 was calculated by combining an estimate of the percentage of immunoreactive cells with an estimate of the staining intensity. Inter tumor MVD was marked by anti-Von Willebrand factor monoantibody. RESULTS: One hundred and forty seven specimens of every pathological phase during the carcinogenesis were obtained which including fourteen hyperplasia, twenty five squamous metaplasia, thirty three dysplasia, twelve carcinoma in situ, fifty four infiltration carcinoma, nine metastasis. The expression of COX-2 and MVD count increased during rat lung carcinogenesis. COX-2 immunohistochemical score was significantly higher in dysplasia, carcinoma in situ and metastasis(P < 0.01, P < 0.05, P < 0.05 respectively), and significant increased MVD were found in carcinoma in situ, infiltration carcinoma and metastasis (P < 0.01). During carcinogenesis, there was a significant correlation between COX-2 expression and MVD(r = 0.9521, P < 0.001, b = 11.51). CONCLUSION: COX-2 may play an important role during the carcinogenesis in experimental rat lung squamous cell carcinoma as well as its metastasis, partly by stimulating angiogenesis.
Assuntos
Carcinoma de Células Escamosas/enzimologia , Isoenzimas/biossíntese , Neoplasias Pulmonares/enzimologia , Neovascularização Patológica , Prostaglandina-Endoperóxido Sintases/biossíntese , Animais , Capilares , Carcinoma de Células Escamosas/induzido quimicamente , Carcinoma de Células Escamosas/patologia , Ciclo-Oxigenase 2 , Feminino , Imuno-Histoquímica/métodos , Neoplasias Renais/secundário , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/patologia , Masculino , Neoplasias Experimentais/induzido quimicamente , Neoplasias Experimentais/enzimologia , Neoplasias Experimentais/patologia , Ratos , Ratos WistarRESUMO
BACKGROUND & OBJECTIVE: Abnormality of FHIT gene has been proved to be frequent in certain malignant tumors closely related to environmental oncogenic factors, such as lung cancer. Foreign scholars have begun to explore the relationship between FHIT gene and other tumor suppressor genes, which are implicated in the pathogenesis of lung cancer. This study was designed to investigate the relationship between hMSH(2) and FHIT protein expression and to explore the correlation of hMSH(2) and FHIT protein expression with clinicopathologic features of lung cancer. METHODS: Immunohistochemical analysis of hMSH(2) and FHIT protein expression in 40 lung cancer cases and 15 adjacent non-cancer lung tissues was performed; the positive rates of FHIT and hMSH(2) proteins were measured by image analysis system. RESULTS: (1)The positive rates of FHIT and hMSH(2) proteins were 58.2% and 45.8% respectively in lung cancer tissues compared with 89.1% and 65.3% in non-cancer lung tissues. The expression levels of FHIT and hMSH(2) proteins were significantly lower in lung cancer tissues than that in non-cancer lung tissues (P< 0.01). (2)Reduced expression levels of both proteins were significantly related to tumor histology. The positive rate of the FHIT protein was 52.2% in squamous cell carcinoma compared with 63.4% in adenocarcinomas(P< 0.01), whereas the positive rate of the hMSH(2) protein was 35.6% in adenocarcinomas compared with 53.2% in squamous cell carcinoma(P< 0.01). (3)A correlation between FHIT reduced expression and lymph node metastasis was observed(P< 0.01). The positive rate of the FHIT protein was 54.1% in lung cancer tissues with metastasis compared with 60.5% in lung cancer tissues without metastasis. No association was found between hMSH(2) reduced expression and nodal metastasis(P >0.05). (4)Loss of FHIT protein correlated significantly with lasting and heavy smoking(P< 0.01). The positive rate of the FHIT protein was 53.1% in smoking group compared with 66.1% in non-smoking group. The reduction of hMSH(2) expression was not associated with smoking(P >0.05). (5)An inverse correlation was found between hMSH(2) reduced expression and FHIT protein loss (P< 0.01, RR=-0.54). CONCLUSION: FHIT gene may be a negative regulatory gene of hMSH(2) gene, and play an important role in the inactivation mechanism of hMSH(2) gene.