Study of tumor growth indicates the existence of an "immunological threshold" separating states of pro- and antitumoral peritumoral inflammation.

Background: Peritumoral inflammation-a response mainly involving polimorphonuclear neutrophils-has traditionally been thought protumoral in its effects. In recent years, however, a number of studies have indicated that it may play an important antitumoral role. This discrepancy has been difficult to explain.

Tumour cell lines HT-29 and FaDu produce proinflammatory cytokines and activate neutrophils in vitro: possible applications for neutrophil-based antitumour treatment.

There is evidence that polymorphonuclear neutrophils (PMNs) can exert severe antineoplastic effects. Cross-talk between tumour cells and endothelial cells (ECs) is necessary for the accumulation of PMN around a tumour. This work reports the ability of two PMN-sensitive, human, permanent cell lines-colorectal adenocarcinoma (HT-29) and pharyngeal squamous-cell carcinoma (FaDu) cells-to act as inflammatory foci.

Position-dependent expression of GADD45alpha in rat brain tumours.

Although the complex and multifactorial process of tumour growth has been extensively studied for decades, our understanding of the fundamental relationship between tumour growth dynamics and genetic expression profile remains incomplete. Recent studies of tumour dynamics indicate that gene expression in solid tumours would depend on the distance from the centre of the tumour. Since tumour proliferative activity is mainly localised to its external zone, and taking into account that generation and expansion of genetic mutations depend on the number of cell divisions, important differences in gene expression between central and peripheral sections of the same tumour are to be expected.

The universal dynamics of tumor growth.

Scaling techniques were used to analyze the fractal nature of colonies of 15 cell lines growing in vitro as well as of 16 types of tumor developing in vivo. All cell colonies were found to exhibit exactly the same growth dynamics-which correspond to the molecular beam epitaxy (MBE) universality class. MBE dynamics are characterized by 1), a linear growth rate, 2), the constraint of cell proliferation to the colony/tumor border, and 3), surface diffusion of cells at the growing edge.