value of immunohistochemical expression of TTF-1, CK7 and CK20 in the diagnosis of primary and secondary lung carcinomas

To study the value of immunohistochemical staining of thyroid transcription factor-1 TTF-1, cytokeratin 7 CK7, and cytokeratin 20 CK20 in the differentiation between primary and secondary pulmonary carcinomas. Forty-three cases of lung carcinoma, 14 squamous cell carcinoma, 12 adenocarcinoma, 8 small cell carcinoma, 3 mesothelioma, and 6 metastatic tumors, were collected from the files of the Pathology Department, King Abdul-Aziz University Hospital, Jeddah, Saudi Arabia between 2004 and 2006. All cases were stained immunohistochemically following Avidin biotin method using monoclonal antibodies to TTF-1, CK7, and CK20. Immunohistochemical staining of 43 cases of lung carcinoma revealed nuclear immunoreactivity for TTF-1 in all primary adenocarcinoma, and small cell carcinoma, while cases of squamous cell carcinoma were negative. Mesotheliomas were negative to TTF-1, CK7, and CK20. Metastatic tumors except for one case metastatic from the thyroid gland were negative to TTF-1. Cytokeratin 7 was positively expressed in primary tumors of lung, as well as metastatic tumors from the thyroid and breast. Cytokeratin 20 was negative in all primary lung tumors, while positive in metastatic carcinomas from the colon. Thyroid transcription factor-1 is a sensitive marker for diagnosis of primary pulmonary adenocarcinoma, and differentiation between poorly differentiated squamous cell carcinoma and small cell carcinoma and adenocarcinoma. Cytokeratin 20 could be a marker for metastatic tumors from the colon to the lung since it was negative in all primary lung tumors

Investigation of the biological significance of p53 tumor suppressor gene and Ki-67 in colorectal carcinoma resected from Saudi patients: An immunohistochemical analysis

p53 protein accumulation has been shown to be an unfavorable prognostic parameter in many human cancers, but findings in colorectal carcinoma [CRC] are equivocal. The objective of this study is to evaluate the value of p53 and Ki-67 as prognostic markers in patients with colorectal carcinoma. We conducted a retrospective analysis on 56 colorectal cancer specimens resected at King Abdulaziz university hospital, Jeddah, Saudi Arabia [40 cases of left colon and 16 from right colon]. Immunohistochemistry [IHC] was performed on formalin fixed paraffin embedded tissue using the avidin-biotin peroxidase complex method. Antibodies to p53 [DO7] and Ki-67 were used. This was correlated with the following clinicopathologic parameters: patient sex, age and survival; pathological stage, and grade of the tumors. Among the 56 cases of colorectal cancer [male/female=1.3; mean age 54.9 years, range 30-80 years], 85.7% [n=48] of tumors were positive for p13 IHC. Ki-67 was positive in 94% [n=53]. The p53 positivity in different stages was as follows [2/2 stage A, 23/28 stage B, 15/18 stage C and 8/8 stage D]. The positivity of p53 according to tumor differentiation was as follows: [well differentiated 6/6, moderately differentiated 38/45, poorly differentiated 4/5]. P53 was positive in 34/40 of left colon [including rectosigmoid] and in 14/16 of right colon carcinoma. Imunoreactivity for p53 was seen in adenomatous epithelium only in 8/22 cases. Although p53 and Ki-67 expression expresse4 strongly in cancer compared to normal tissue [p<0.05], there was no relation with survival, grade or Dukes' stage of the tumor. P53 cannot be considered as independent prognostic marker in colorectal carcinoma