Desmoid-type fibromatosis: toward a holistic management

PURPOSE OF REVIEW

Desmoid-type fibromatosis, a rare locally aggressive fibroblastic proliferation, is a treatment challenge. This review aimed to explore recent data about the management of desmoid-type fibromatosis.

RECENT FINDINGS

New data underline the role of kinases and ɣ-secretase in stimulating cell proliferation and invasiveness in desmoid-type fibromatosis. This explains the proven activity of multikinase inhibitors (sorafenib or pazopanib) in the management of desmoid-type fibromatosis or the emerging role of a ɣ-secretase inhibitor. An international guideline for management was recently published, and this guideline take into account patient point of view. Lastly, recent studies highlight the multidimensional burden of desmoid-type fibromatosis, particularly health-related quality of life (HRQoL).

SUMMARY

Active surveillance with planned MRI is the first-line management in desmoid-type fibromatosis. A site-specific and stepwise approach should be considered for progressive desmoid-type fibromatosis. Further, a risk-benefit analysis that considers the side effects and long-term sequelae should be conducted before deciding to start any treatment. A less aggressive approach should be considered. Multikinase inhibitors are effective, but their tolerability and side effects should be discussed with the patients. The symptoms and HRQoL should be integrated in decision-making. Desmoid-type fibromatosis patients should be offered support to address their needs supportive care.

Telomere length and telomerase activity in extra-abdominal desmoid tumors

The telomere biology of extra-abdominal desmoids was investigated. In 12 specimens, telomere length was assessed by Southern-blot analysis and telomerase activity was measured using a PCR-based TRAP assay. There was a significant correlation between telomere length and tumor size, with telomeres being shorter with increasing tumor size (p = 0.049), and between telomere length and PCNA-positive cell rate, with telomere shortening with increased positive cell rate (p = 0.017). There was a significant correlation between telomerase activity and age at surgery, with increased activity with younger age (p = 0.015). Telomere length increased with recurrence, but telomerase activity decreased, and rate of PCNA-positive cells became lower, whenever the tumors were recurrent. Decreasing telomere length correlated with tumor size, probably due to increased duration of proliferation in the tumor, and tumor aggressiveness. Recurrent case results may be due to a lower rate of cell division and the presence of telomerase activity.

Invasion and MMP expression profile in desmoid tumours

Desmoid tumours are locally invasive soft tissue tumours in which β-catenin mediated TCF-dependent transcription is activated. The role of soluble factors secreted by the myofibroblastic desmoid tumour, which could stimulate tumour invasiveness, was investigated. Using collagen gel invasion assays, the presence of factors stimulating invasion in desmoid conditioned media (CM) could be established. Since matrix metalloproteinases (MMPs) have been implicated in the process of tumoral invasion, the expression levels of the MMP family members were evaluated. Quantitative reverse transcription–PCR was used to determine the expression levels of MMP1, MMP2, MMP3, MMP7, MMP11, MMP12, MMP13, MMP14 and the inhibitors TIMP1, TIMP2 and TIMP3. Besides overexpression of MMP7, a known TCF-dependent target gene, a striking upregulation of the expression levels of MMP1, MMP3, MMP11, MMP12 and MMP13 in desmoid tumours, compared to unaffected fibroblasts from the same patients, was found. Treating the CM of desmoids with a synthetic and a physiologic MMP inhibitor reduced the invasion-stimulating capacity of the desmoid CM by approximately 50%. These results suggest the involvement of soluble factors, released by the desmoid cells, in stimulating invasion and implicate the MMPs as facilitators of invasion.

Lack of telomerase in desmoids occurring sporadically and in association with familial adenomatous polyposis

BACKGROUND

Telomerase activity may be required for unlimited growth of cells and is repressed in most somatic tissues, but is detectable in immortal cell lines, germ cells, many malignancies and some benign lesions. Desmoids are proliferative, locally invasive, non-metastasizing fibromatous tumours which rarely regress. They occur frequently in familial adenomatous polyposis (FAP), causing significant morbidity and death. Telomerase activity was assayed in desmoids from patients with and without FAP to assess the role of telomerase in the development of these lesions, and its potential as a prognostic marker and possible target for treatment.

METHODS

Protein extracts from 11 desmoids from nine patients with FAP, and ten desmoids from ten patients without FAP, were analysed for telomerase activity by the telomeric repeat amplification protocol, a sensitive polymerase chain reaction-based assay. Six fibrosarcomas and a fibrosarcoma cell line were used as positive controls; all displayed telomerase activity.

RESULTS

No telomerase activity was detected in any of the 21 desmoids studied.

CONCLUSION

These results indicate that desmoid tumours are one of the intriguing exceptions to the emerging view that re-expression of telomerase activity accompanies the development of preneoplastic and neoplastic tissues, and suggest that alternative mechanisms may operate in these proliferative neoplasms.