Immunohistochemistry of lung carcinomas for cytokeratins and neuroendocrine markers

Cytokeratins:

	pan-keratin	AE1	AE3	BG-8	Cam5.2	35BH11 (LMW CK)	34bE1234b2(HMW CK)	B72.3
small cell carcinoma	36/375	6/65	11/115	4/65	5/65	19/3515	12% (1/375, 3/43 (variously bronchial biopsies, FNAs or bronchial washings)14, 9/35 (some cases counted as positive showed reactivity of 1-10% of cells)15, 7/56 (the positive foci were composed of larger cells and suggested minimal squamous or glandular differentiation.)13, 3/4314, 9/3515, 0/1016)	2/375
carcinoid							0/50 (27 typical and 23 atypical. Entrapped bronchial epithelium is intensely positive)13, 0/10 (5 typical and 5 atypical)14
large cell carcinoma (non-endocrine)	9/95						8/95	4/95
large cell neuroendocrine	6/65						1/6 (One case showed positivity but in less than 10% of cells.)5, 1/44 (One case showed scattered weakly positive cells.)10, 11/64 (in all cases, <10% of cells stained)13, 0/214	3/65
adenocarcinoma	33/335	8/85	8/85	7/85	8/85		14/335, 8/2610, 10/10 (variously bronchial biopsies, FNAs or bronchial washings: poorly differentiated)14	29/335
bronchioloalveolar see also mucinous bronchioloalveolar	13/135	3/35	3/35	2/35	3/35		12/135
adenosquamous carcinoma
basaloid carcinoma							5/514
squamous cell carcinoma	37/375	12/125	12/125	10/125	12/125		97%(36/375, 12/1210, 28/2810, 15/16 (variously bronchial biopsies, FNAs or bronchial washings: poorly differentiated. Staining was focal - less than 5% of tumour cells)14, 22/23 (basaloid squamous cell carcinomas)16)	31/375

	CK5/6	CK7	CK14	CK17	CK19	CK20
small cell carcinoma	0%21, 1/30 (positivity only in a squamous component)22	2/385, 2/117, 11%21,11/30 (dot-like)22	2/375, 1/76, 5%21	2/385	80%21,23/30 (dot-like)22	0/115, 0/117, 1%21,0/3022
carcinoid	10%21, 0/2322	2/912, 10/1611, 21%21,1/2322	0/96		20%21,16/2322	0/912, 0/1611, 0%21,0/2322
large cell carcinoma (non-endocrine)	0/2522	5/95,10/2522	6/95	6/95	9/2522	0/617,0/2522
large cell neuroendocrine	17%21, 3/1022	2/65, 33%21,7/1022	1/65, 17%21	0/65	0%21, 8/10 (dot-line in some cases)22	1/1022
adenocarcinoma	0/3022	31/335, 45/547, 70/748, 80/8020, 30/3022	7/335, 2/106	5/335	30/3022,8/1022, 30/3022	0/85, 6/547, 6/748, 6/699, 13/212 (5 cases with <25% of cells positive, 3 cases with 26-50% of cells positive, 2 cases with 51-75% of cells positive, 3 cases with >75% of cells positive. Positive cases were 6 mixed, 4 acinar and 3 papillary.)17, 10/80 ( positivity focal in six cases, 10-25% of cells in one case, 26-75% in one case and >75% in two cases)20,1/3022
bronchioloalveolar see also mucinous bronchioloalveolar	0/1422	13/135, 3/37 , 26/26 (positivity in 51-75% of tumour in one case, >75% in 25 cases)18, 14/1420,13/1422	5/135	1/135	14/1422	0/35, 0/37, 1/26 (positivity in 26-50% of tumour in one case)18, 4/14 ( positivity 10-25% of cells in one case, 26-75% in one case and >75% in two cases20,0/1422
adenosquamous carcinoma	squamous component 3/3, glandular component 1/322	squamous component 0/3, glandular component 2/322			3/3 (both components positive)	0/322
squamous cell carcinoma	30/30 (predominantly intense diffuse and membrane staining: less strong in poorly differentiated tumoura.)22	8/375, 0/127, 7/30 (positivity often seen in areas without either squamous or glandular differentiation)22	35/375, 13/156	34/375	30/3022	0/125, 1/127, 0/4117,1/30 (positivity of 5% of cells in one case)22

In combined large cell neuroendocrine carcinomas, only the squamous component (6/6¹³) or adenocarcinomatous component (5/6¹³) shows positivity for 34betaE12: combined small cell / squamous cell carcinomas show positivity of the squamous cell component (3/3¹³), but combined small cell / large cell neuroendocrine carcinomas show no positivity (0/5¹³).

Neuroendocrine markers:

	CD 56	chromogranin	synaptophysin
small cell carcinoma	64/662, 8/1014	37% (7/662, 32/385, 8/181, 19/43 (with microwave treatment: 4/43 without microwave treatment)14, 8/3515)	54% (27/662, 21/365, 9/1014, 23/3515)
carcinoid	9/11 (nine cases showed tumour cell membrane staining: the remaining two showed staining of sustentacular cells)3, 7/1014	15/17 (foregut carcinoids: 11 lung, 4 gastric and 2 duodenal)%3, 10/10 (5 typical and 5 atypical)14	11/11%3, 8/10 (4/5 typical add 4/5 atypical)14
large cell carcinoma (non-endocrine)	2/32	0/32, 1/95	0/32, 1/95
large cell neuroendocrine	2/22, 40/4410, 2/214	0/22, 30/4410, 5/65, 2/2 (with microwave treatment)14	2/22, 37/4410, 6/65, 2/2 (focal - less than 5% of tumour cells)14
adenocarcinoma	1/382, 0/254, 1/10 (poorly differentiated)14	0/382, 3/671, 2/335, 0/10 (poorly differentiated)14	1/382, 2/335, 0/10 (poorly differentiated)14
bronchioloalveolar		0/135	0/135
basaloid carcinoma	3/2810, 1/5 (focal - less than 5% of cells)14	0/2810, 1/514	1/2810, 1/514
squamous cell carcinoma	4/522, 0/254, 2/16 (poorly differentiated)14	1/522, 2/375, 0/16 (poorly differentiated)14	1/522, 0/355, 0/16 (poorly differentiated)14

Other neuroendocrine markers in small cell carcinoma: bombesin; 28/35¹⁵, neurofilament; 24/35¹⁵, NSE; 21/35¹⁵, ACTH; 0/35¹⁵

Diagnostic utility

Differentiation of non-small cell carcinoma from small cell carcinoma⁵. 34bE123, CK5/6, CK14 and CK17 all preferentially stain squamous cell carcinomas. If the threshold is set at 10% of cells showing immunoreactivit, 34bE12 excludes all neuroendocrine tumours. CK7 and B72.3 stain adenocarcinomas, where they have a complementary role; those adenocarcinomas staining weakly with one tend to stain strongly with the other. Conversely, small cell carcinomas are usually positive for CD 56, chromogranin and synaptophysin.

Differentiating the intermediate type of small cell carcinoma from poorly differentiated squamous cell carcinoma ("small cell variant") may be particularly difficult. Small cell carcinoma is more likely to be positive for CD56 and to show punctate positivity for Cam5.2. Non-small cell carcinoma is more likely to be positive for 34bE12 and CK5/6. Cytokeratin 14 should be positive in squamous cell carcinoma, but my personal experience is that in poorly differentiated squamous cell carcinoma it is often negative. p63 and TTF-1 both have the advantage of being nuclear stains, avoiding the problem of scant cytoplasm in small cell carcinoma and in the small cell variant of squamous cell carcinoma: they have been applied in a panel to previously Papanicolaou-stained cytological smears and cytospin preparations²⁴.

	p16	p63	TTF-1	34bE12
small cell carcinoma	28/28 (high level of staining in 27 cases, low level in one case)23	0/23 (17 tissue and 6 cytology)19, 0/2823, 0/13 (this study was performed using a panel of p63 and TTF-1 on previously Papanicolaou - stained cytological smears and cytospin preparations)24	20/23 (17 tissue and 6 cytology)19, 26/2823, 12/13 (this study was performed using a panel of p63 and TTF-1 on previously Papanicolaou - stained cytological smears and cytospin preparations)24	0/2823
poorly differentiated squamous cell carcinoma	15/28 (includes seven cases with a component of small call variant of squamous carcinoma, which had the same profile as the oncventional poorly differentiated squamous cell carcinoma)23	13/13 (12 tissue and 1 cytology)19, 28/28 (includes seven cases with a component of small call variant of squamous carcinoma, which had the same profile as the oncventional poorly differentiated squamous cell carcinoma)23, 13/13 (this study was performed using a panel of p63 and TTF-1 on previously Papanicolaou - stained cytological smears and cytospin preparations)24	0/13 (12 tissue and 1 cytology)19, 1/28 (includes seven cases with a component of small call variant of squamous carcinoma, which had the same profile as the oncventional poorly differentiated squamous cell carcinoma)23, 0/13 (this study was performed using a panel of p63 and TTF-1 on previously Papanicolaou - stained cytological smears and cytospin preparations)24	28/28 (includes seven cases with a component of small call variant of squamous carcinoma, which had the same profile as the oncventional poorly differentiated squamous cell carcinoma)23

While immunoreactivity for increases with the degree of keratinisation, staining for p63 shows an inverse relation to keratinisationa nd is therefore particualrly yuseful inprroly differentiated squamous cell carcinomas²³. p16 may be positive in TTF-1-negative small cell carcinomas²³.

Large cell neuroendocrine carcinomas are often positive for CK7, while carcinoid tumours are almost invariably negative.  

References

¹ Noguchi M. Hirohashi S. Shimosato Y. Immunohistochemical detection of cluster 1 small cell lung cancer antigen and chromogranin A in lung carcinomas. Japanese Journal of Clinical Oncology 1992 22(1):6-9.

² Kaufmann O. Georgi T. Dietel M. Utility of 123C3 monoclonal antibody against CD56 (NCAM) for the diagnosis of small cell carcinomas on paraffin sections. Human Pathology. 28(12):1373-8, 1997.

³ Al-Khafaji et al. Immunohistologic analysis of gastrointestinal and pulmonary carcinoid tumours. Human Pathol 1998;29:992-9.

⁴ Lantuejoul S. Laverriere MH. Sturm N. Moro D. Frey G. Brambilla C. Brambilla E. NCAM (neural cell adhesion molecules) expression in malignant mesotheliomas. Human Pathology 2000;31(4):415-21.

⁵ Lyda, M. H., Weiss, L. M.. Immunoreactivity for epithelial and neuroendocrine antibodies are useful in the differential diagnosis of lung carcinomas. Human Pathol 2000;31:890-897.

⁶ Chu, P. G., Lyda, M. H., Weiss, L. M. Cytokeratin 14 expression in epithelial neoplasms: a survey of 435 cases with emphasis on its value in differentiating squamous cell carcinomas from other epithelial tumours. Histopathology 2001;39:9-16.

⁷ Coordinate expression of cytokeratins 7 and 20 defines unique subsets of carcinomas. NP Wang et al. Applied Immunohistochemistry 1995; 3:99-107.

⁸ Loy TS, Calaluce RD. Utility of cytokeratin immunostaining in separating pulmonary adenocarcinomas from colonic carcinomas. Am J Clin Pathol 1994;102:764-767.

⁹ Miettinen M. Keratin 20: immunohistochemical marker for gastrointestinal, urothelial and Merkel cell carcinomas. Mod Pathol 1995;8:384-388.

¹⁰ Sturm, N., Lantuejoul, S., Laverriere, M. H., Papotti, M., Brichon, P. Y., Brambilla, C., Brambilla, E. Thyroid transcription factor 1 and cytokeratins 1, 5, 10, 14 (34betaE12) expression in basaloid and large-cell neuroendocrine carcinomas of the lung. Hum Pathol 2001;32:918-925.

¹¹ Cai, Y. C., Banner, B., Glickman, J., Odze, R. D. Cytokeratin 7 and 20 and thyroid transcription factor 1 can help distinguish pulmonary from gastrointestinal carcinoid and pancreatic endocrine tumors. Human Pathol 2001;32:1087-1093

¹² Chu, P., Wu, E., Weiss, L. M. Cytokeratin 7 and cytokeratin 20 expression in epithelial neoplasms: a survey of 435 cases. Mod Pathol 2000;13:962-972

¹³ Sturm, N., Rossi, G., Lantuejoul, S., Laverriere, M.H., Papotti, M., Brichon, P.Y., Brambilla, C. and Brambilla, E. 34betaE12 expression along the whole spectrum of neuroendocrine proliferations of the lung, from neuroendocrine cell hyperplasia to small cell carcinoma. Histopathology 2003;42:156-166.

¹⁴ Viberti, L., Bongiovanni, M., Croce, S. and Bussolati, G. 34betaE12 Cytokeratin Immunodetection in the Differential Diagnosis of Small Cell Tumors of Lung. Int J Surg Pathol 2000;8:317-322.

¹⁵ Shy, S.W., Lee, W.H., Chou, M.C., Lai, Y.S. and Tu, Y.C. Small cell lung carcinoma: clinicopathological, immunohistochemical, and ultrastructural study. J Surg Oncol 1990;45:146-61.

¹⁶ Morice, W.G. and Ferreiro, J.A. Distinction of basaloid squamous cell carcinoma from adenoid cystic and small cell undifferentiated carcinoma by immunohistochemistry. Hum Pathol 1998;29:609-12.

¹⁷ Yatabe, Y., T. Koga, et al. (2004). "CK20 expression, CDX2 expression, K-ras mutation, and goblet cell morphology in a subset of lung adenocarcinomas." J Pathol 203(2): 645-52.

¹⁸ Goldstein, N. S. and M. Thomas (2001). "Mucinous and nonmucinous bronchioloalveolar adenocarcinomas have distinct staining patterns with thyroid transcription factor and cytokeratin 20 antibodies." Am J Clin Pathol 116(3): 319-25.

¹⁹ Wu, M., B. Wang, et al. (2003). "p63 and TTF-1 immunostaining. A useful marker panel for distinguishing small cell carcinoma of lung from poorly differentiated squamous cell carcinoma of lung." Am J Clin Pathol 119(5): 696-702.

²⁰ Shah, R. N., S. Badve, et al. (2002). "Expression of cytokeratin 20 in mucinous bronchioloalveolar carcinoma." Hum Pathol 33(9): 915-20.

²¹ Erickson, L. A. and R. V. Lloyd (2004). "Practical markers used in the diagnosis of endocrine tumors." Adv Anat Pathol 11(4): 175-89.

²² Jerome Marson, V., J. Mazieres, et al. (2004). "Expression of TTF-1 and cytokeratins in primary and secondary epithelial lung tumours: correlation with histological type and grade." Histopathology 45(2): 125-34.

²³ Zhang H, Liu J, Cagle PT, Allen TC, Laga AC,Zander DS Distinction of pulmonary small cell carcinoma from poorly differentiated squamous cell carcinoma: an immunohistochemical approach. Mod Pathol 2005; 18:111-8

²⁴ Kalhor N, Zander DS,Liu J. TTF-1 and p63 for distinguishing pulmonary small-cell carcinoma from poorly differentiated squamous cell carcinoma in previously pap-stained cytologic material. Mod Pathol 2006; 19:1117-23

This page last revised 12.8.2006.