Classification of tumours

Abstract

Tumours are classified according to the most differentiated cells with the exception of carcinomas where a few tumour cells show neuroendocrine differentiation. In this case these cells are regarded as redifferentiated tumour cells, and the tumour is not classified as neuroendocrine. However, it is now clear that normal neuroendocrine cells can divide, and that continuous stimulation of such cells results in tumour formation, which during time becomes increasingly malignant. To understand tumourigenesis, it is of utmost importance to recognize the cell of origin of the tumour since knowledge of the growth regulation of that cell may give information about development and thus possible prevention and prophylaxis of the tumour. It may also have implications for the treatment. The successful treatment of gastrointestinal stromal tumours by a tyrosine kinase inhibitor is an example of the importance of a correct cellular classification of a tumour. In the future tumours should not just be classified as for instance adenocarcinomas of an organ, but more precisely as a carcinoma originating from a certain cell type of that organ.

Accuracy of breast magnetic resonance imaging in evaluating the response to neoadjuvant chemotherapy: a study of 310 cases at a cancer center

“…Although neoadjuvant chemotherapy (NAC) for breast cancer was initially used only as a salvage therapy for inoperable tumors, it has since made significant progress toward being an accepted treatment in other contexts. It is now more widely used and has been shown to be as effective as is postoperative adjuvant therapy ( 1 - 3 ) , with potential advantages such as primary tumor shrinkage-possibly leading to conversion from mastectomy to breast-conserving surgery and from axillary lymph node dissection to sentinel lymph node biopsy-as well as eliciting better patient responses, as determined by in vivo evaluation and by detection of a pathological complete response (pCR). Achieving a pCR has been proposed as a surrogate endpoint for long-term clinical benefit, given that had greater overall and disease-free survival have been shown to be better in patients who achieve a pCR, which has greater prognostic value in aggressive (triple-negative and HER2+) tumor subtypes ( 4 ) .…”

Consensus Diagnoses and Mode of Action for the Formation of Gastric Tumors in Rats Treated with the Chloroacetanilide Herbicides Alachlor and Butachlor

“…The alteration of the neuroendocrine architecture of the fundic mucosa, although initially reversible, when subject to sustained chronicity, leads to cellular dysplasia of proliferating ECL cells at different stages of maturity and finally to cellular autonomy consistent with neoplasia IARC 2003;Martinsen et al 2003;Waldum et al 2008). Phenotypic variability in the alachlor and butachlor tumors is due to dedifferentiation with redifferentiation and to ECL cell-induced paracrine effects.…”

Role and Therapeutic Potential of Melatonin in Various Type of Cancers

“… 8 In many tumors classified as adenocarcinomas based on glandular growth pattern and/or tumor cell positivity for PAS or Alcian blue, which are believed to contain mucin, there are tumor cells with neuroendocrine properties. 9 Classification of tumors based on the cell of origin of carcinomas seems to be the best system to help understand the biological significance of carcinogenesis, gain insight on new possibilities for prevention and early treatment, and possibly develop new drugs for the treatment of tumors. 9 …”

“… 9 Classification of tumors based on the cell of origin of carcinomas seems to be the best system to help understand the biological significance of carcinogenesis, gain insight on new possibilities for prevention and early treatment, and possibly develop new drugs for the treatment of tumors. 9 …”