TTF-1 monoclonal comparison

The monoclonal antibody against TTF-1, SPT24, appears to have greater sensitivity, at the expense of loss of specificity, by comparison with the clone 8G7G3/1. Most published studies have used the latter clone.

Immunohistochemical expression

SPT24 showed more intense staining of pneumocytes than did 8G7G1/1¹.

	scoring (0 no expression or faint expression of <5% of the tumor nuclei, 1 when faint expression of >=5% of the tumor nuclei, 2 when bright expression of >=5% of the tumor nuclei. 1 and 2 were considered as positive staining.)	SPT24 from Novocastra	8G7G3/1 from Dako
	Primary pulmonary adenocarcinoma	72/861	56/86 (all positive cases were also positive with SPT24. 13 cases with a score of "1" scored "2" using SPT24)1
	Primary colorectal carcinoma	4/90 (using tissue microarrays: the positive cases showed staining of 20-40~% of nuclei, often associated with cytoplasmic staining.)1	0/901
	Lung metastases from primary colorectal adenocarcinoma	4/41 (Staining was seen in 10-40% of the nuclei of the positive cases. In two cases, nuclear staining was associated with cytoplasmic staining. All had documented colorectal primaries, with lung metastases showing the typical morphology of colorectal metastases and all CK7-/CK20+. In all three cases where suitable material was available, extra-pulmonary tumour was also TTF-1 positive.)1	0/41 (both primaries and lung metastases were negative. One case showed very faint nuclear graying, below the threshold for positivity.)1
	Lung metastases from renal carcinoma	0/61	0/61
	Lung metastases from breast carcinoma	0/21	0/21

References

¹Eva Compérat, Fan Zhang, Cedric Perrotin, Thierry Molina, Pierre Magdeleinat, Beatrice Marmey, Jean-Francois Régnard, Josee Audouin and Saphie Camilleri-Broët. Variable sensitivity and specificity of TTF-1 antibodies in lung metastatic adenocarcinoma of colorectal origin. Modern Pathology, advance online publication 29 April 2005.

This page last revised 15.6.2005.

©SMUHT/PW Bishop