ROLE OF TL-201 CHLORIDE AND TC-99M METHOXY-ISOBUTYL-ISONITRITE (SESTAMIBI) IN EVALUATION OF BREAST MASSES - CORRELATION WITH THE IMMUNOHISTOCHEMICAL CHARACTERISTIC PARAMETERS (KI-67, PCNA, BCL-2, AND ANGIOGENESIS) IN MALIGNANT LESIONS

The aim of this project was to study the kinetics of both T1 and Tc-99 m MIBI in PBM by evaluating tumor to normal tissue ratio in early (E) images acquired within 1/2 hour and delayed (D) images acquired three hours following the I.V. injection of 3 mCi (111 MBq) of Tl and 20 mCi (740 MBq) of MIBI an 2 separate days in 49 patients. The washout inde x was calculated from E ratio minus D ratio divided by E ratio. A nega tive ratio indicating build up of activity in D images and a positive ratio indicated washout of activity from the E images. In addition, th e findings were correlated with the following immunohistochemical para meters: pathological grading, number of cells in mitotic division (PCN A- Ki-67), angiogenesis (well formed and ill formed blood vessels) and presence or absence of Bcl 2 Oncogene (release antiapoptotic signals) . Results showed that in all benign and malignant lesions, MIBI showed consistent washout varying from 19-27% while with Tl, there was persi stent washout in all benign lesions and mixed washout or buildup varyi ng from + 16% to minus 17% in malignant lesions. (E) ratios showed a r easonable correlation between Tl and MIBI (r = 0.5). There was more si gnificant correlation between the D ratios (r = 0.8). Due to high (E) MIBI uptake ratios and their higher percentage of washout than Tl, del ayed ratios came close to each other. Immunohistochemical analysis rev ealed benign lesions presented with low mitotic rate: Ki-67 (71.4%), P CNA (14.2%), low amount of ill formed blood vessels (42.8%) and high a mount well formed blood vessels (100%). While malignant lesions presen ted with high mitotic rate Ki-67 was (96.7%), PCNA (100%), high amount of ill formed blood vessels (73.3% in GII and 100% in Grade III) and less amount of well formed blood vessels of 90% and 83.4% in Grade II and III respectively. Bcl-2 was variable in both benign and malignant lesions with 71.4% in benign, 73.4% in GII and 16.7 in cm malignancy. In conclusion, early uptake ratio in both benign and malignant tumors is related to the degree of angiogenesis, percentage of ill formed blo od vessels, high mitotic activity reflected by high grade of tumor and high percentage of PCNA and Ki-67.