A 56 year old chronic smoker, mass in bronchus resected. What is the possible marker:
**Core Concept:**
The question is asking about possible markers in a patient with a resected mass in the bronchus, likely due to a lung cancer. Markers in oncology are biological characteristics that can be detected in body fluids or tissues to diagnose, monitor, or predict the prognosis of a disease. In this case, we are looking for markers that might indicate the presence of lung cancer.
**Why the Correct Answer is Right:**
The correct answer is **D**: TTF-1 (Thyroid Transcription Factor-1). TTF-1, also known as NKX2-1, is a transcription factor expressed in lung, thyroid, and other tissues. In lung cancer, TTF-1 is typically expressed in adenocarcinoma cells, which makes it a useful marker for lung cancer diagnosis, particularly in cases where histopathological examination is inconclusive or when the tumor cannot be easily identified.
**Why Each Wrong Option is Incorrect:**
A) Carcinoembryonic antigen (CEA) is a marker of gastrointestinal cancers, particularly colon cancer. It is not specific for lung cancer.
B) CYFRA 21-1 is a marker for squamous cell carcinoma, another type of lung cancer, but it is not specific for adenocarcinoma.
C) Calcitonin is a marker for medullary thyroid carcinoma and parathyroid adenoma, not lung cancer.
**Clinical Pearl:**
In clinical practice, the presence of TTF-1 in a resected mass can help confirm the diagnosis of lung adenocarcinoma, thus influencing treatment decisions and prognosis. However, it is essential to consider other markers and pathological features alongside TTF-1 to confirm the diagnosis.
**Correct Answer:** D) TTF-1