Test positive for poorly differentiated non small cell carcinoma compatible with adenocarcinoma. Is this a cancer that started in another part of the body and went to lung and is it a fast growing cancer? What is positive strongly for TTF-1 and Napsin mean, and also strongly positive for pan keratin.

Hello Carolyn:

I do apologize for the delay in responding to your question.

This cancer has started in the lung. It can be difficult to ascertain if an adenocarcinoma - cancer with gland like cell formation - is originating from lung or has metastasized (arrived from other site) from another organ.

This dilemma is resolved using staining for specific proteins TTF1 and Napsin. If these two are positively stained in tumor cells, origin from lung is confirmed. Pan keratin being positive indicates tumor is of epithelial origin and not from neural or soft tissue origin.

It is an aggressive tunit.

Wish you all the best


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Neha Dahiya MD


Help patients understand the medical terminology of their lab results and / or tissue biopsy reports.


I am a pathologist and director of clinical laboratory services. I have been a practicing pathologist for last 9 years in a 350 bed multi specialty hospital laboratory in India.

Indian association of pathologists and microbiologists.
International Academy of Cytology
International association of Pathologists - Indian division
Indian association of Cytology

MD (pathology) MBA

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