**Core Concept**
MIC-2 is a cell surface antigen, specifically a type of glycoprotein, which plays a crucial role in the diagnosis of various hematological malignancies. This antigen is expressed on the surface of certain types of T cells and is used as a marker for identifying specific types of leukemia.

**Why the Correct Answer is Right**
The MIC-2 antigen is a diagnostic marker for Ewing's Sarcoma, a type of malignant bone tumor that primarily affects children and young adults. The expression of MIC-2 on the surface of tumor cells is a key feature of this disease and is used in conjunction with other diagnostic tests to confirm the diagnosis. The MIC-2 antigen is recognized by the monoclonal antibody OKT6, which is used in immunohistochemical analysis to identify Ewing's Sarcoma cells.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because MIC-2 is not a marker for acute lymphoblastic leukemia (ALL). While ALL is a type of leukemia that affects T cells, MIC-2 is not a specific marker for this disease.

**Option B:** This option is incorrect because MIC-2 is not a marker for lymphoma. Lymphomas are a diverse group of cancers that affect the immune system, but MIC-2 is not a diagnostic marker for any type of lymphoma.

**Option C:** This option is incorrect because MIC-2 is not a marker for neuroblastoma. Neuroblastoma is a type of cancer that affects the nervous system, but MIC-2 is not a diagnostic marker for this disease.

**Clinical Pearl / High-Yield Fact**
The MIC-2 antigen is a specific marker for Ewing's Sarcoma and is used in conjunction with other diagnostic tests to confirm the diagnosis. Immunohistochemical analysis using the monoclonal antibody OKT6 is a key tool in identifying MIC-2 expression on tumor cells.

**Correct Answer:** C.