Cytoplasmic TTF-1 in hepatocellular carcinoma

Cytoplasmic staining with TTF-1 has been little studied. It is unclear whether cytoplasmic staining is due to TTF-1 or a cross-reacting antigen. The limitation of gene expression to the lung (and thyroid) suggests the latter¹⁰. The staining is usually granular. Staining is seen with a biotin-free protocol⁸, although several authors used a biotin-based system in combination with HIER: false perinuclear positivity due to endogenous biotin may sometimes appear. The diffuse cytoplasmic staining of hepatocytes (and hepatocellular carcinoma) is seen only with clone 8G7G3/1 (DakoCytomation and others)⁹, not with clone SPT24 (NovoCastra)⁸.

Immunohistochemical expression

In a large series of consecutive cases, about 6% (23/361) of all tumours from a variety of sites showed cytoplasmic staining⁹.

• a minority of pulmonary adenocarcinomas show coarse granular cytoplasmic staining^2,9 (& personal observation).

• occasionally in squamous carcinomas of the lung, head, neck and cervix^5,6.

• occasional positivity in oncocytic thyroid tumours³.

• perinuclear staining in small and large intestine⁴.

• perinuclear staining in pancreatic ductal and acinar cells⁴.

• some gastrointestinal and pancreatic carcinoids⁴

• Colonic adenocarcinoma⁹.

• Rather commonly in decalcified bone⁹.

• Cytoplasmic immunoreactivity appears to be much more common in hepatocellular carcinomas than in other adenocarcinomas. The table below gives results in hepatocellular carcinoma and its mimics, with Hep Par 1 for comparison.

	cytoplasmic TTF-1	Hep Par 1
Benign liver tissue	27/279
hepatocellular carcinoma	54/76 (2/2 grade 1, 28/38 grade 2, 20/28 grade 3, 3/7 grade 4 and 1/1 fibrolamellar.)1, 9/97	50/761
adenocarcinoma	3/851, 6/47 (pulmonary, cytological preparations)2, 1/49 (non-pulmonary, cytological preparations)2, 0/137	1/831
renal cell carcinoma	0/721	0/741
adrenal cortical carcinoma	0/221	0/211

¹Threshold for positivity 5% of tumour cells.

There appears to be considerable variation in cytoplasmic staining between commercial antibodies and with different buffers¹¹:

		Dako		Zymed		Santa Cruz		Novocastra		Hepar-1
	buffer:	EDTA	DTRS	EDTA	DTRS	EDTA*	DTRS	EDTA	DTRS
	Hepatocellular carcinoma	54/77	45/77	31/77	11/77	53/77	5/77	0/77	0/77	64/77
	pulmonary adenocarcinoma	12/12, nuclear positivity only
	renal cell carcinoma (n=41)	negative
	adrenocortical carcinoma (n=20	negative
	urothelial carcinoma (n=19)	negative
	oral and oesophageal squamous cell carcinoma (n=11)	negative
	salivary gland tumours (n=37)	negative
	gastric (n=16)adenocarcinoma	negative
	colorectal adenocarcinoma (n=17)	negative
	pancreatic adenocarcinoma (n=11)	2/11		negative
	prostatic adenocarcinoma (n=25)	negative
	gynaecological carcinoma (n=31)	2/6 mucinous ovarian tumours		negative
	breast carcinoma (n=35)	negative
	thyroid carcinoma (n=20)	20/20, nuclear positivity only
	mesothelioma (n=11)	negative
	* Santa Cruz antibody with EDTA produced non-specific cytoplasmic staining in 28 different tumours

The lack of cytoplasmic staining with the Novocastra antibody may make interpretation of nuclear staining easier.

Diagnostic utility

• Diagnosis of hepatocellular carcinoma and differentiation from renal cell carcinoma, adrenocortical carcinoma and adenocarcinoma NOS.

• FNA approaches to the kidney and adrenal may transverse the liver. Positivity for Hep par 1 and cytoplasmic TTF-1 may help to identify adventitious hepatocytes. Positive reactive hepatocytes should not be mistaken for hepatocellular adenocarcinoma.

References

¹Wieczorek, T. J., J. L. Pinkus, et al. (2002). "Comparison of thyroid transcription factor-1 and hepatocyte antigen immunohistochemical analysis in the differential diagnosis of hepatocellular carcinoma, metastatic adenocarcinoma, renal cell carcinoma, and adrenal cortical carcinoma." Am J Clin Pathol 118(6): 911-21.

²Hecht, J. L., Pinkus, J. L., Weinstein, L. J., Pinkus, G. S. The value of thyroid transcription factor-1 in cytologic preparations as a marker for metastatic adenocarcinoma of lung origin Am J Clin Pathol 2001;116:483-488.

³Bejarano, P. A., Y. E. Nikiforov, et al. (2000). "Thyroid transcription factor-1, thyroglobulin, cytokeratin 7, and cytokeratin 20 in thyroid neoplasms." Appl Immunohistochem Mol Morphol 8(3): 189-94.

⁴Agoff, S. N., L. W. Lamps, et al. (2000). "Thyroid transcription factor-1 is expressed in extrapulmonary small cell carcinomas but not in other extrapulmonary neuroendocrine tumors." Mod Pathol 13(3): 238-42.

⁵Kaufmann, O. and M. Dietel (2000). "Expression of thyroid transcription factor-1 in pulmonary and extrapulmonary small cell carcinomas and other neuroendocrine carcinomas of various primary sites." Histopathology 36(5): 415-20.

⁶Kaufmann, O. and M. Dietel (2000). "Thyroid transcription factor-1 is the superior immunohistochemical marker for pulmonary adenocarcinomas and large cell carcinomas compared to surfactant proteins A and B." Histopathology 36(1): 8-16.

⁷Chen S et al. Value of thyroid transcription vactor (TTF-1) and anti-hepatocyte monoclonal antibodies in differentiating hepatocellular carcinoma (HHC) from metastatic adenocarcinoma (MA) in liver [abstract]. Mod Pathol 2001;14:193A.

⁸Communication from Aalborg Sygehus, NordiQC.

⁹Bejarano, P. A. and F. Mousavi (2003). "Incidence and significance of cytoplasmic thyroid transcription factor-1 immunoreactivity." Arch Pathol Lab Med 127(2): 193-5.

¹⁰Giordano, T. J., K. A. Shedden, et al. (2001). "Organ-specific molecular classification of primary lung, colon, and ovarian adenocarcinomas using gene expression profiles." Am J Pathol 159(4): 1231-8.

¹¹Pan, C. C., P. C. Chen, et al. (2004). "Cytoplasmic immunoreactivity for thyroid transcription factor-1 in hepatocellular carcinoma: a comparative immunohistochemical analysis of four commercial antibodies using a tissue array technique." Am J Clin Pathol 121(3): 343-9.

This page last revised 8.11.2003.

©SMUHT/PW Bishop