Molecular Targeting of the Human Epidermal Growth Factor Receptor-2 (HER2) Genes across Various Cancers

Human epidermal growth factor receptor 2 (HER2) belongs to the ErbB family, a group of four transmembrane glycoproteins with tyrosine kinase activity, all structurally related to epidermal growth factor receptor (EGFR). These tyrosine kinases are involved in the transmission of cellular signals controlling normal cell growth and differentiation. If this transmission goes awry, it can lead to dysregulated growth of the cell. HER2 specifically can be implicated in the pathogenesis of at least eight malignancies. HER2 positivity quickly became a well-characterized indicator of aggressiveness and poor prognosis, with high rates of disease progression and mortality. After realizing the implication of HER2, it first became investigated as a target for treatment in breast cancer, and later expanded to areas of research in other cancer types. To this day, the most therapeutic advancements of anti-HER2 therapy have been in breast cancer; however, there have been strong advancements made in the incorporation of anti-HER2 therapy in other cancer types as well. This comprehensive review dissects HER2 to its core, incorporating the most up to date information. The topics touched upon are discussed in detail and up to 200 published sources from the most highly recognized journals have been integrated. The importance of knowing about HER2 is exemplified by the groundbreaking advancements that have been made, and the change in treatment plans it has brought to the oncological world in the last twenty years. Since its groundbreaking discovery there have been significant breakthroughs in knowledge regarding the actual receptor, the receptors biology, its mechanism of action, and advancements in tests to detect HER2 and significant strides on how to best incorporate targeted treatment. Due to the success of this field thus far, the review concludes by discussing the future of novel anti-HER2 therapy currently in development that everyone should be aware of.

Disparity in the use of combined modality therapy for rectal cancer in the older adult

OBJECTIVES

The standard treatment strategy for patients with rectal adenocarcinoma having T3 or T4 tumors or positive lymph nodes includes concurrent chemoradiation, surgery and chemotherapy. Population based studies show relatively low rates of usage of standard therapy for rectal cancer in the older adult.

MATERIALS AND METHODS

Two decades of cases of stage II and stage III rectal cancer from two academic teaching hospitals were reviewed. Comparisons were made of subjects ≤70 or ≥71years with regard to initiation and completion of radiation, chemotherapy and surgery.

RESULTS

Subjects ≥71years of age had significantly lower proportions of surgical resection (84 vs. 94%) and of initiation of all three component of standard therapy (49 vs. 66%) compared to those ≤70years of age. Subjects ≥71years had significantly more co-morbidities; however, the difference in initiation of therapy remained after adjusting for stage, treating hospital, co-morbid status, race or sex in multivariable analysis. The odds for initiation of therapy were reduced by ≈22% in older adults in the adjusted analysis. Among all patients who started therapy only 56% completed it without dose reduction or delay. There were trends to increased completion among those receiving neo-adjuvant vs. post-operative chemoradiation and among those with stage III as opposed to stage II cancer.

CONCLUSIONS

Our study indicates that a major disparity in the use of standard therapy for rectal cancer in the older adult exists in academic hospital settings. It will be important for oncologists to reconsider increasing the usage of curative therapy in these patients.