WHAT CAUSES BREAST CANCER?
A study conducted by scientists at the University of New South Wales, Australia for 83 years has revealed that 40 % of breast cancer strains may be transmitted by human-to-human saliva.
The study has also linked some breast cancers to a virus linked to the domestic rat.
According to the experts, there is enough evidence that a mouse mammary tumour-like virus (MMTV) is the probable cause of many breast cancers.
The mammary tumour-like virus was first discovered in rat milk in 1936. It was later linked to tumours in pups which were suckled by cancerous mothers.
Since then, research has constantly linked women with breast cancer to a higher evidence of the MMTV virus in their body tissues.
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BREAST CANCER MOST RECENT STATISTICS (2019)
Another study conducted in Kenya in 1981 also linked the mice virus to up to 40 % of breast cancers.
This study led to the discovery that 13 out of 21 which translates to 62% of breast cancer patients in Kenya and 27 out of 145 that is 18.6 % of breast cancer patients in the US had signs of the MMTV virus.
Among Asian women, 38% of breast cancer patients had the virus.
In healthy women who did not have breast cancer, 0nly 7 out of 26 (27%) had evidence of the MMTV
virus. In Asia, one out of 22 healthy women had the MMTV virus (4.5%).
On the other hand, one out of 36 healthy women in America had the mice virus (2.8%).
The authors of this new breast cancer study explained that the high levels of MMTV virus among Kenyan women compared to Asian and American women suggest different strains of the disease, environmental or genetic factors.
THE DANGERS OF THE HOUSE MICE
They also said that the high population in third world countries like Kenya may lead to wider exposure of these women to domestic rats as opposed to developed countries.
House mice are common in Kenyan households. They do defecate and urinate on uncooked food which exposes humans to greater danger.
Rats are also common in supermarkets and shops which stock cereals and other products that human beings eat without cooking.
According to the study, the MMTV virus which is present in many rodent populations can be transmitted by consuming uncooked cereals and other uncooked products.
The study concludes that the higher the prevalence of the house mice, the higher the prevalence of human breast cancer.
BREAST CANCER QUICK FACTS
- Women with breast cancer have five times more mice viruses than healthy women.
- The MMTV virus that causes breast cancer can be identified between 1 and 11 years before the cancer develops beyond control.
- The virus is also present in human milk from normal lactating women but it is higher in lactating women at a higher risk of breast cancer.
- The MMTV virus is also present in dogs, cats, mice, rats and monkeys.
- Saliva is the most plausible means of transmitting the breast cancer virus from human to human and possibly fro dogs to humans.
Breast cancer is a malignant growth that develops in the breasts. It is a disease which is characterized by abnormal and uncontrolled multiplication of cells in the breast tissues.
It is treatable if diagnosed early
It also requires a medical diagnosis- a biopsy
Lab tests and imaging are required to help in diagnosis
It is one of the most common types of cancer, especially among American women.
One in every eight women in the US develops breast cancer
It has got various types which differ depending on their ability to spread to other parts of the body.
It does not have specific causes but medics have identified several risk factors.
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COMMON TYPES OF BREAST CANCER
There are many types of breast cancer but the most common ones are:
- Ductal carcinoma in situ
- Invasive ductal carcinoma
- Invasive lobular carcinoma
Most breast cancers encompass a type of carcinoma called adenocarcinoma which starts in the cells that make up glands (the glandular tissue. This means that their onset is in the milk ducts or the lobules (milk-producing glands)
Less common types of breast cancer include:
Sarcomas, Phyllodes, Paget disease& Angiosarcomas. These start in the cells of the muscle, fat or connective tissue
It is also crucial to note that sometimes a single breast cancer can be as a result of the combination of various types of cancers. Moreover, in some rare cases, the cancer cells may fail to form a lump or a tumour at all.
Therefore, the pathologist needs to conduct a biopsy to determine the specific type of cancer and check if the cancer has spread and if it has, to what extent. The extent to which the cancer has developed can be described using the following terms:
In situ which means that the breast cancers have not spread
Invasive or infiltrating which means that the cancers have invaded or spread to the surrounding tissues
EARLY SIGNS AND SYMPTOMS OF BREAST CANCER
- Swelling of part of the breast or the whole of it
- Consistent breast and/or nipple pain
- Nipple retraction. This means that the nipples are turned inwards
- A red, scaly or thickened nipple and/or breast skin
- Abnormal nipple discharge (a discharge other than breast milk)
- Skin irritation or when the breast skin looks like an orange peel
- Swollen lymph nodes in the neck and armpits
- A change in the size or shape of the breast or nipples
Usually, normal breast cells become cancerous due to DNA mutations-abnormal changes. Although some of these mutations are inherited, most DNA mutations are acquired in the course of the patient’s life. This occurs when proto-oncogenes which help cells to grow mutate, they can facilitate increased growth of cells in a way that cannot be controlled. This uncontrolled growth of cells is what causes breast cancers. Such mutations are referred to as oncogenes
Risk factors include:
- Family history- breast cancer is common among women whose close relatives i.e. mother, sister or daughter have ever diagnosed with cancer.
- The patient’s history- if you have ever been diagnosed with breast cancer in one of the breasts, you are at a higher risk of developing cancer in the other breast or an additional cancer on the original breast.
- Obesity- being overweight increases the risk of breast cancer in pre and postmenopausal women
- The use of oral contraceptives for a long period that is at least 10 years slightly increases the risk of developing breast cancer.
- Failure to breastfeed a child for at least one and a half years increases the risk. However, breastfeeding for one and a half to two years might lower the risk.
- Exposure to chest radiations or the use of diethylstilbestrol further increases the risk
- Race- white women are likely to develop breast cancer whereas African-American women tend to have developed tumours that are more aggressive if they develop into cancer
- Women who have ever been diagnosed with certain non-cancerous breast conditions for instance typical hyperplasia are at a greater risk of developing breast cancer.
- Menstruation- women who start their menstruation cycle at a younger age (before 12 years) or those who experience menopause later (after 55 years) have a slightly higher risk of developing breast cancer
- The density of the breast tissue- women whose breast tissue is dense (can be measured using a mammogram) have a higher risk of developing breast cancer.
- Alcohol consumption also increases the risk. A recent meta-analysis proved that all amounts or levels of alcohol are directly linked to an increased risk of breast cancer development, light drinking included.
- Lack of exercise also increases the risk of breast cancer development.
- Genetic risk factors- if you inherit a mutated gene from a parent, then there is a significantly higher risk of developing breast cancer.