**Core Concept**
Elevated serum alpha fetoprotein (AFP) levels are often associated with certain types of cancers, particularly those originating from the liver. Alpha fetoprotein is a protein normally produced by the yolk sac and fetal liver during fetal development, but its levels typically decrease after birth. In adults, elevated AFP levels can indicate liver damage or the presence of a malignant tumor.

**Why the Correct Answer is Right**
Hepatocellular carcinoma (HCC) is a primary malignancy of the liver, and it is one of the most common cancers associated with elevated AFP levels. This is because HCC often produces AFP as a tumor marker, which can be detected in the blood. The production of AFP by HCC cells is thought to be a result of the re-expression of genes that were normally silenced in adult liver cells. Elevated AFP levels in a chronic alcoholic are particularly concerning for HCC, as chronic alcohol abuse is a known risk factor for liver cirrhosis and subsequent HCC development.

**Why Each Wrong Option is Incorrect**
**Option A:** Prostatic adenocarcinoma is not typically associated with elevated AFP levels. While some prostate cancers may produce PSA (prostate-specific antigen) as a tumor marker, AFP is not a common marker for this type of cancer.

**Option B:** Multiple myeloma is a plasma cell malignancy that can produce various proteins, including monoclonal immunoglobulins. However, it is not typically associated with elevated AFP levels.

**Option D:** Glioblastoma multiforme is a primary brain tumor that is not typically associated with elevated AFP levels. While some brain tumors may produce various proteins as tumor markers, AFP is not a common marker for glioblastoma multiforme.

**Clinical Pearl / High-Yield Fact**
Elevated AFP levels in adults should prompt a thorough evaluation for liver disease or malignancy, particularly in individuals with a history of chronic alcohol abuse or hepatitis.

**✓ Correct Answer: C. Hepatocellular carcinoma**