Cancer Biology & Pathology Flashcards

In ICD-O-3, what does a behavior code of '/3' indicate?

Answer: Malignant, primary site

Behavior code '/3' in ICD-O-3 designates a malignant primary site tumor, distinguishing it from benign ('/0'), borderline ('/1'), and metastatic ('/6') designations.

Which histologic type of lung cancer is most commonly diagnosed in non-smokers and women?

Answer: Adenocarcinoma

Adenocarcinoma is the most frequent lung cancer subtype in non-smokers and women, often arising peripherally in the lung and associated with EGFR mutations.

Carcinoma in situ (CIS) is best defined as:

Answer: Malignant cells confined to the epithelium with no basement membrane invasion

Carcinoma in situ consists of malignant epithelial cells that have not yet breached the basement membrane, making it non-invasive by definition.

Tumor grade primarily describes which characteristic of a neoplasm?

Answer: The degree of cellular differentiation relative to normal tissue

Tumor grade reflects how closely cancer cells resemble normal cells microscopically; low-grade tumors are well-differentiated and high-grade tumors are poorly differentiated.

Adenocarcinoma is a malignancy arising from which tissue type?

Answer: Glandular epithelium

Adenocarcinoma (prefix 'adeno-') originates from glandular epithelial cells and is common in organs such as the colon, breast, lung, and prostate.

Which laboratory technique uses antibodies to detect specific proteins expressed by tumor cells and is routinely reported on pathology reports?

Answer: Immunohistochemistry (IHC)

Immunohistochemistry (IHC) applies labeled antibodies to tissue sections to visualize protein expression, commonly used to classify tumors and guide targeted therapy selection.

A pathology report describes a tumor as 'poorly differentiated.' What does this indicate to the tumor registrar?

Answer: The tumor cells bear little resemblance to normal tissue and tend to be aggressive

Poorly differentiated (high-grade) tumors have cells that look very abnormal under the microscope, correlating with more aggressive behavior and typically worse prognosis.