行政院國家科學委員會補助專題研究計畫成果報告:犬乳癌預後因子與人類乳癌動物模式適用性之探討

Mammary gland tumor is a spontaneous and common disease in aged dogs. In the past decades, canine mammary gland tumor has been chosen as a potential etiological, pathogenetic, and therapeutic model for human breast tumor, but very little or limited studies is known about the mammary gland tumor in Taiwan. A total of 435 canine tumors during a 6-year period (1995-2002) was collected and analyzed. Mammary tumors (32.0%, 139/435) were second to the skin and soft tissue tumors (45.3%; 197/435). Based on the sex, it was listed the most common neoplasm in the female dogs (48.2%; 132/274) and the affected mammary glands were mostly located in the 4th and 5th pairs. The malignant type was more than benign type (1.1:1) and over 50% of malignant tumors showed the evidence of angiolymphatic invasion by pathological examination. In histopathological classification according to WHO standard classification( 1999), benign mixed tumor( 42 cases, 30.2 %) was the most common and followed by tubulopapillary carcinoma (37 cases, 26.6%) and complex carcinoma( 18 cases, 13.0%). In the present study, 10 to 12 years old dogs(47 cases, 33.8
were predisposed to have tumor development, followed by 7 to 9 years old (40 cases, 28.8%) and 4 to 6 years old (26 cases, 18.7%) . Sex prevalence showed that females and non-ovanectomy (118 cases, 84.9%) were predominant. Owing to the living environmental limitation, small breed dogs including Mongrel(54 cases, 38.9% )and Maltese( 17 cases, 12.2%), were popular and more liable to present tumor than other breeds in Taiwan. A total of 35 cases were analysed inmiunohistochemically for hormone receptors and oncogen expression. The ER positive rate was 25.7% (9/35) including 33.3% (5/15) of benign cases and 20.0% (4/20) of malignant cases. PR positive rate was 85.7% (30/35) including 93.3% (14/15) of benign cases and 80.0% (16/20) of malignant cases. The ratios that both ER and PR positive (ER+PR+) was 22.9% (8/35) , ER +PR¡X was 2.9% (1/35), ER¡XPR+ was 62.9% (22/35), and ER¡XPR¡X was 11.4% (4/35). The HER-2/neu overexpression rates were 5 3.2% (42/79) which consisted of 51.1% (24/47) of malignant cases and 56.3%( 18/32 )of benign cases. Among the benign tumors, benign mixed tumor was diagnosed in 12 cases and HER-2/neu overexpression was 15.2%. Retrospective study of the survival time was evaluated in 39 cases. The malignant and benign survival intervals were 1 to 36 month( 12.7 months in average)and 12 to 42 months( 22.7 months in average). In malignant cases, 63.6% (14/22) of survival time was less 1 year, and mortality caused by tumor recurrence was
59.1%( 13/22). In 17 dogs with benign tumors, survival time was all over 1 year. On conclusion, the malignant tumors had less expression of ER and PR and shortening survival time than benign cases, but HER-2/neu overexpression was inconclusive.