Which tumors are indicated by an increase in PTH-like peptide?

An increase in PTH-like peptide (PTHrP) is associated with several types of tumors, and the correct answer indicates that this phenomenon is not limited to just one type of malignancy. PTHrP mimics the action of parathyroid hormone (PTH) and can lead to hypercalcemia through bone resorption and increased renal tubular reabsorption of calcium.

In hepatocellular carcinoma, PTHrP production can contribute to the paraneoplastic hypercalcemia often seen in patients. Similarly, renal adenocarcinoma can produce PTHrP, leading to similar effects. Squamous cell carcinoma of the lung is also well-known for its association with hypercalcemia due to PTHrP secretion, which is often referred to as a paraneoplastic syndrome.

The presence of elevated PTHrP in these various tumors illustrates the concept of paraneoplastic syndromes where tumors produce substances that result in hormonal effects far removed from the actual tumor site. Hence, the increase in PTH-like peptide is a common feature in these malignancies, underscoring its significance as a marker for multiple cancers.