| Theme |
Early Colorectal Cancer -- Recent Topics |
| Title |
Molecular Biology of Early Colorectal Cancer |
| Author |
Miyuki Takata |
Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University |
| Author |
Takashi Yao |
Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University |
| Author |
Masazumi Tsuneyoshi |
Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University |
| [ Summary ] |
The multistep genetic model of colorectal carcinogenesis is based on the concept of the adenoma-carcinoma sequence. The adenoma-carcinoma sequence theory has been generally accepted for polypoid early colorectal cancers. On the other hand, an increasing number of superficial cancers have been reported. It is known that many nonpolypoid carcinoma lesions are pure cancers without any adenomatous components, so some claim that these lesions develop by de novo carcinogenesis. Early nonpolypoid cancers have distinct characteristics histologically and genetically, in contrast to early polypoid cancers, which follow the adenoma-carcinoma sequence. It has been suggested that nonpolypoid cancers have a defferent pathway for carcinogenesis from that of polypoid cancers. However, molecular events related to nonpolypoid cancers, such as the de novo pathway, have yet to be clarified. Further molecular analysis, especially nonpolypoid early colorectal cancers, is important in the development of diagnostics and treatment of early colorectal cancers. |