Histologic and Immunochemical Assessment of Colorectal Cancers

Dale Telgenhoff; Brooke Dubansky; Sally Lewis

doi:10.29074/ascls.2022003207

Article Figures & Data

Tables

View popup

Table 1.

Histological morphology of tumors with H&E staining

Histologic Morphology
Grade 1 (low)	Well differentiated: tumor mimics surrounding tissue morphology, gland formation, mucous production
Grade 2 (low)	Moderate differentiation: gland formation decreased (50%–75%), some recapitulation of normal features
Grade 3 (high)	Poorly differentiated: glands present but disorganized, decreased greatly; difficult to ascertain normal architecture
Grade 4 (high)	Undifferentiated: parent tissue morphology no longer recognizable

Preliminary observation of the tumor using H&E staining may be useful in the designation of low- or high-grade tumor. Additional investigation, special stains, and immunohistochemistry are required for an in-depth examination of the tumor.

View popup

Table 2.

CRC staging

Standard Treatment for CRC Based on Stage
Stage	Description	Treatment
Stage 0	Carcinoma in situ	Surgery for removal (if margins on polyp not clear)
Stage I	Low grade, no nodal involvement	Surgery (as above)
Stage II	High grade, no nodal involvement	Surgery (as above)
Stage III	Any grade, invasion of lymph nodes	Surgery and adjuvant chemotherapy
Stage IV	Metastatic	Surgery, chemotherapy, radiation

The CRC stage is determined at the time of diagnosis and involves the tumor characteristics (T), regional or distant lymph node involvement (N), and metastasis (M). Any metastatic tumor is automatically stage IV regardless of the T and N scoring. Treatment becomes more aggressive as the stage increases and may include other therapies beyond the traditional surgery, chemotherapy, and radiation. (Adapted from the PDQ Adult Treatment Editorial Board colon cancer treatment guidelines.¹⁵)

View popup

Table 3.

Common markers used in screening, diagnosis, and prognosis of CRC

Common Markers for CRC
Marker	Description	Notes
CEA	Carcinoembryonic antigen	Serum or IHC (tumor), nonspecific. Monitor response to therapy
CRP	C-reactive protein	Serum, nonspecific inflammation
AE1/AE3	Pancytokeratin	IHC, tumor of epithelial origin (carcinoma)
CK7	Cytokeratin 7	IHC, CRC negative (differentiation from other tumor types)
CK20	Cytokeratin 20	IHC, CRC positive (differentiation from other tumor types)
MUC2	Mucin 2	IHC, mucinous CRC
AMACR	α-Methyacyl-CoA racemase	IHC, increased in some CRC
Ki-67	Ki-67 nuclear protein	IHC, marker of proliferation
APC	Adenomatous polyposis coli	IHC, tumor suppressor protein
p53	Phosphoprotein p53	IHC, tumor suppressor protein
B-Raf	B-Raf protein kinase	Serum, IHC, genetic screening (proto-oncogene)
K-Ras	K-Ras GTPase	Serum, IHC, genetic screening (proto-oncogene)
MMR	Mismatch repair proteins	Serum, IHC, genetic screening (MLH1, MSH2, MSH6, PMS2)