| Mammary tumors are the most common tumors in female dogs.Early diagnosis of this disease is difficult as it can be easily confused with cysts and nodules,among other conditions.The occurrence and development of mammary tumors can seriously harm the health of female dogs.In recent years,with the increasing level of pet disease diagnosis and treatment,the differential diagnosis of canine mammary tumors(CMT)has received more and more attention.The rapid development of molecular biology has led to the development and application of more specific mammary tumor markers,providing a new avenue for the early diagnosis,prognosis,and treatment of mammary tumors.Mi RNAs are tiny non-coding RNA molecules widely present in animals that regulate various physiological processes.Their expression levels differ significantly between normal tissues and benign/malignant tumor tissues,and they are expected to become biomarkers for the differential diagnosis of CMT.There are few reports on the application of miRNAs in canine mammary tumors.Because of this,this study analyzed the tissue expression of six miRNAs and combined them with multiple clinical indicators to evaluate their diagnostic value for canine mammary tumors.To investigate the incidence pattern of CMT,this study surveyed 205 cases of CMT in some areas of Shandong from 2018 to 2022,analyzing the relationship between the occurrence of mammary tumors and the breed,age,dietary habits,estrus status,and affected mammary gland region of the affected dogs.Tumor tissues were identified by histopathological and imaging examinations to determine their nature,type,degree of differentiation,and grading.This study referred to relevant literature on miRNAs research at home and abroad.Initially,it determined miR-21,miR-24,miR-29 b,miR-155,miR-214,and miR-502 as research objects to analyze the relationship between these six miRNAs and mammary tumors.A total of 60 mammary tumor tissues from affected dogs were collected in this experiment.The expression levels of miRNAs in tumor tissues and adjacent tissues of affected dogs were detected by real-time fluorescent quantitative polymerase chain reaction(RT-q PCR).Mi RNAs with high sensitivity and reasonable specificity were selected for combined detection to analyze whether they have diagnostic significance for the differential diagnosis of benign/malignant tumors and early malignant tumors.The expression levels of miRNAs were correlated with clinical indicators to explore their application value diagnosing of CMT.The main results are as follows:(1)A total of 632 cases of canine neoplastic diseases were collected in this study,and all205 cases of CMT were female dogs.Among the 205 confirmed cases of CMT,22 breeds were involved,with the highest incidence rate in poodles,accounting for 39.02% of the total,followed by mixed breed dogs,accounting for 20.98% of the total.The incidence rate of CMT increases with age,with 91.22% of affected dogs over seven years old.The diet of most affected dogs was mainly meat mixed with dog food and pure dog food,accounting for36.59% and 35.61% of the total number of affected dogs,respectively.The average estrus frequency for dogs is twice a year,and 77.56% of affected dogs had an increased or decreased estrus frequency.64.39% of affected dogs had never given birth.During the study period,the survival rate of mammary tumor cases with a diameter less than 3cm was 90.09%,while the survival rate of mammary tumor cases with a diameter greater than 3cm was 74.47%.(2)This study performed histopathological examination on mammary tumors from 60 affected dogs.The results showed 39 cases of benign tumors,accounting for 65% of the total,and 21 cases of malignant tumors,accounting for 35% of the total.The routine hematological examination has little diagnostic significance for mammary tumors.Based on histopathological examination,mammary tumors were divided into three groups: malignant group,benign group,and control group(adjacent tissue).According to the Elston and Ellis scoring system,21 cases of malignant tumors were divided into three groups: grade I group,grade II group,and grade III group.RT-q PCR detected the expression levels of six miRNAs in different groups.The results showed that the expression levels of miR-21,miR-155,miR-214,and miR-502 were significantly different between the malignant,benign,and control groups.The expression level of miR-29 b was significantly different between the control and benign and the malignant groups.The expression level of miR-24 was not very different between groups.In the comparison between the malignant grade I group,the grade II group,and the grade III group,only the expression level of miR-502 was significantly different between groups,and its expression level was positively correlated with the degree of malignancy of mammary tumors.(3)The highest sensitivity in single detection was miR-21(0.976),the highest specificity was miR-214(0.974)and miR-502(0.974),and the highest Youden index was miR-21(0.694).Combined detection can improve the diagnosis value.The largest area under the receiver operating characteristic curve was the triple detection of miR-21,miR-155,and miR-214(0.940).In correlation analysis,the expression levels of four miRNAs,miR-21,miR-155,miR-214,and miR-502,were correlated with the number of globulins and the albumin/globulin ratio but not with other indicators.In summary,the incidence rate of CMT in some areas of Shandong is related to multiple factors such as breed,age,estrus frequency,and reproductive status.Imaging and hematological indicators have certain limitations in the differential diagnosis of benign/malignant mammary tumors.The four selected miRNAs: miR-21,miR-155,miR-214,and miR-502,can potentially become candidate biomarkers for the diagnosis and prognosis of CMT.Mi R-502 can potentially become a candidate biomarker for the early diagnosis of malignant mammary tumors in CMT. |
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